lecture 20
play

Lecture 20 March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun - PowerPoint PPT Presentation

. . . . .. . . .. . . .. . . .. . . .. . . Lecture 20 March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang March 28th, 2013 Hyun Min Kang Uniformly Most Powerful Test Biostatistics 602 - Statistical Inference ..


  1. , X . . Example . .. . . .. . .. Pr . . .. . . .. . i.i.d. Pr Pr Note that X i March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . n X n , and n .. c n X Pr c n n X . .. . . . . .. . . .. . . .. . .. .. . . .. . . .. . . . 5 / 1 .. .. . .. . . . . . . .. . . .. . . .. . ∼ N ( θ, σ 2 ) where σ 2 is known, testing H 0 : θ ≤ θ 0 vs X 1 , · · · , X n H 1 : θ > θ 0 . LRT test rejects H 0 if x − θ 0 σ / √ n > c . ( X − θ 0 ) σ / √ n > c β ( θ ) = ( X − θ + θ − θ 0 ) = σ / √ n > c

  2. , X .. . . .. . . .. . . . .. . . .. . . .. .. i.i.d. Example Note that X i March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . n X n , and n . c n X Pr Pr Pr Pr . . .. . . . .. . . .. . .. .. . . .. . . .. . . . 5 / 1 . . . . .. . . . .. . .. .. . .. . . .. . . ∼ N ( θ, σ 2 ) where σ 2 is known, testing H 0 : θ ≤ θ 0 vs X 1 , · · · , X n H 1 : θ > θ 0 . LRT test rejects H 0 if x − θ 0 σ / √ n > c . ( X − θ 0 ) σ / √ n > c β ( θ ) = ( X − θ + θ − θ 0 ) = σ / √ n > c ( X − θ σ / √ n + θ − θ 0 ) σ / √ n > c =

  3. . .. .. . . .. . .. . . . .. . . .. . . . .. . n , and March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . n X , X . Note that X i Pr Pr Pr Pr i.i.d. Example .. . . .. .. . .. .. . . . . . .. . . .. . . . . .. .. . . .. . . .. . . .. . . . 5 / 1 . .. . . ∼ N ( θ, σ 2 ) where σ 2 is known, testing H 0 : θ ≤ θ 0 vs X 1 , · · · , X n H 1 : θ > θ 0 . LRT test rejects H 0 if x − θ 0 σ / √ n > c . ( X − θ 0 ) σ / √ n > c β ( θ ) = ( X − θ + θ − θ 0 ) = σ / √ n > c ( X − θ σ / √ n + θ − θ 0 ) σ / √ n > c = ( X − θ σ / √ n > c − θ − θ 0 ) = σ / √ n

  4. . .. . . .. . . .. . . .. . . .. . . . . Pr March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang Pr Pr Pr i.i.d. . Example . .. . . .. .. .. . .. . .. . . .. . . .. .. . . .. . . . 5 / 1 . .. . . .. . . . . . .. . . .. . . .. ∼ N ( θ, σ 2 ) where σ 2 is known, testing H 0 : θ ≤ θ 0 vs X 1 , · · · , X n H 1 : θ > θ 0 . LRT test rejects H 0 if x − θ 0 σ / √ n > c . ( X − θ 0 ) σ / √ n > c β ( θ ) = ( X − θ + θ − θ 0 ) = σ / √ n > c ( X − θ σ / √ n + θ − θ 0 ) σ / √ n > c = ( X − θ σ / √ n > c − θ − θ 0 ) = σ / √ n Note that X i ∼ N ( θ, σ 2 ) , X ∼ N ( θ, σ 2 / n ) , and X − θ σ / √ n ∼ N (0 , 1) .

  5. . .. .. . .. . . .. . . .. . . .. . . . . Because the power function is increasing function of March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . Therefore the LRTs are unbiased. always holds when , Pr . Example (cont’d) . .. . . .. .. . . . . .. .. . . .. . . .. . . .. . . .. . . . . . .. . . .. . .. 6 / 1 .. . . .. . . Therefore, for Z ∼ N (0 , 1) ( Z > c + θ 0 − θ ) σ / √ n β ( θ ) =

  6. . . .. .. . .. . . .. . . .. . . .. . .. . . . .. . . .. . Example (cont’d) Pr always holds when . Therefore the LRTs are unbiased. Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . . .. .. . . .. . . .. . . .. . . . . . .. . . . .. . . .. . . .. . .. . . .. 6 / 1 . Therefore, for Z ∼ N (0 , 1) ( Z > c + θ 0 − θ ) σ / √ n β ( θ ) = Because the power function is increasing function of θ , β ( θ ′ ) ≥ β ( θ )

  7. . .. . .. .. . .. . . .. . . .. . . . .. . .. . . .. . . .. . Example (cont’d) Pr Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . . . .. . . .. . . .. . . .. . . .. . . . . . .. . . .. . . 6 / 1 .. . .. . .. . . Therefore, for Z ∼ N (0 , 1) ( Z > c + θ 0 − θ ) σ / √ n β ( θ ) = Because the power function is increasing function of θ , β ( θ ′ ) ≥ β ( θ ) always holds when θ ≤ θ 0 < θ ′ . Therefore the LRTs are unbiased.

  8. . .. . . .. . . .. . . .. . . .. . . . . Definition March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang function of another test in C . . . . . Uniformly Most Powerful Test (UMP) . .. . . .. .. .. . . .. . .. . . .. . . .. . . .. . . .. . . . . . .. . .. .. . . .. . . .. . . 7 / 1 Let C be a class of tests between H 0 : θ ∈ Ω vs H 1 : θ ∈ Ω c 0 . A test in C , with power function β ( θ ) is uniformly most powerful (UMP) test in class C if β ( θ ) ≥ β ′ ( θ ) for every θ ∈ Ω c 0 and every β ′ ( θ ) , which is a power

  9. • A UMP test is ”uniform” in the sense that it is most powerful for • For simple hypothesis such as H . . . .. . . .. . . . .. . . .. . . .. .. . c . March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang test always exists. , UMP level and H every . in this class. c test has the smallest type II error probability for any UMP level . . . .. .. . .. .. . . .. . . . .. . .. . . .. . . . . .. .. . . .. . . .. . . . . . .. . . .. . 8 / 1 UMP level α test Consider C be the set of all the level α test. The UMP test in this class is called a UMP level α test.

  10. • A UMP test is ”uniform” in the sense that it is most powerful for • For simple hypothesis such as H . . .. . . .. . .. . . . .. . . .. . . .. c . March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang test always exists. , UMP level and H every . in this class. . . . .. . .. . .. .. . . . .. . . . . . .. . . .. . . . .. .. . . .. . . .. . . .. . .. . . . .. . 8 / 1 UMP level α test Consider C be the set of all the level α test. The UMP test in this class is called a UMP level α test. UMP level α test has the smallest type II error probability for any θ ∈ Ω c 0

  11. • For simple hypothesis such as H . . .. . . .. . . .. .. . . .. .. . . . . in this class. March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang test always exists. , UMP level and H . . . . .. . . .. .. . . . . .. .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . 8 / 1 .. . . .. . . UMP level α test Consider C be the set of all the level α test. The UMP test in this class is called a UMP level α test. UMP level α test has the smallest type II error probability for any θ ∈ Ω c 0 • A UMP test is ”uniform” in the sense that it is most powerful for every θ ∈ Ω c 0 .

  12. . . . .. .. . .. . . .. . . .. . . .. . .. .. . . .. . . .. . . . in this class. Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . . . .. . . .. . . .. . . .. . . .. . . . . . .. . . .. . . 8 / 1 . . . .. . .. .. UMP level α test Consider C be the set of all the level α test. The UMP test in this class is called a UMP level α test. UMP level α test has the smallest type II error probability for any θ ∈ Ω c 0 • A UMP test is ”uniform” in the sense that it is most powerful for every θ ∈ Ω c 0 . • For simple hypothesis such as H 0 : θ = θ 0 and H 1 : θ = θ 1 , UMP level α test always exists.

  13. • (Sufficiency) Any test that satisfies 8.3.1 and 8.3.2 is a UMP level • (Necessity) if there exist a test satisfying 8.3.1 and 8.3.2 with k . . and kf x if f x R x R that satisfies . Theorem 8.3.12 - Neyman-Pearson Lemma R c . Neyman-Pearson Lemma . .. . . .. . . .. x kf x if f x every UMP level March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . A Pr X A satisfying Pr X test satisfies 8.3.1 except perhaps on a set A test (satisfies 8.3.2), and .. test is a size then every UMP level , test , Then, R Pr X and For some k . . .. .. . .. . . .. . . .. . . . .. . .. . . .. . . .. . . . . . .. . .. . . .. . . .. . . . . . .. . . .. . . .. 9 / 1 Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where the pdf or pmf corresponding the θ i is f ( x | θ i ) , i = 0 , 1 , using a test with rejection region

  14. • (Sufficiency) Any test that satisfies 8.3.1 and 8.3.2 is a UMP level • (Necessity) if there exist a test satisfying 8.3.1 and 8.3.2 with k . . x R that satisfies . . Theorem 8.3.12 - Neyman-Pearson Lemma . Neyman-Pearson Lemma .. if f x . . .. . . .. . . .. R c For some k kf x test satisfies 8.3.1 except perhaps on a set A March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . A Pr X A satisfying Pr X every UMP level . test (satisfies 8.3.2), and test is a size then every UMP level , test , Then, R Pr X and . .. .. .. . .. . . .. . . .. . . . .. . .. . . .. . . .. . . . . . .. . .. . . .. . . .. . . . . . .. . . .. 9 / 1 Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where the pdf or pmf corresponding the θ i is f ( x | θ i ) , i = 0 , 1 , using a test with rejection region x ∈ R if f ( x | θ 1 ) > kf ( x | θ 0 ) (8 . 3 . 1) and

  15. • (Sufficiency) Any test that satisfies 8.3.1 and 8.3.2 is a UMP level • (Necessity) if there exist a test satisfying 8.3.1 and 8.3.2 with k . . . Theorem 8.3.12 - Neyman-Pearson Lemma . Neyman-Pearson Lemma . .. . R that satisfies .. . . .. . . .. .. . . and For some k test satisfies 8.3.1 except perhaps on a set A March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . A Pr X A satisfying Pr X every UMP level . test (satisfies 8.3.2), and test is a size then every UMP level , test , Then, R Pr X .. . . .. .. . . .. . . .. . . . .. . .. . . .. . . .. . . . 9 / 1 . . . .. . . .. . . .. .. .. . . .. . . . . Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where the pdf or pmf corresponding the θ i is f ( x | θ i ) , i = 0 , 1 , using a test with rejection region x ∈ R if f ( x | θ 1 ) > kf ( x | θ 0 ) (8 . 3 . 1) and x ∈ R c if f ( x | θ 1 ) < kf ( x | θ 0 ) (8 . 3 . 2)

  16. • (Sufficiency) Any test that satisfies 8.3.1 and 8.3.2 is a UMP level • (Necessity) if there exist a test satisfying 8.3.1 and 8.3.2 with k . . Neyman-Pearson Lemma . .. . . .. . Theorem 8.3.12 - Neyman-Pearson Lemma .. . . .. . . .. . . . . satisfying Pr X March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . A Pr X A test satisfies 8.3.1 except perhaps on a set A .. every UMP level test (satisfies 8.3.2), and test is a size then every UMP level , test R that satisfies . .. . . . . .. . . .. . .. . . . .. . . .. . . . .. . .. .. . . .. . . .. . . .. . . . .. . .. . . 9 / 1 Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where the pdf or pmf corresponding the θ i is f ( x | θ i ) , i = 0 , 1 , using a test with rejection region x ∈ R if f ( x | θ 1 ) > kf ( x | θ 0 ) (8 . 3 . 1) and x ∈ R c if f ( x | θ 1 ) < kf ( x | θ 0 ) (8 . 3 . 2) For some k ≥ 0 and α = Pr ( X ∈ R | θ 0 ) , Then,

  17. • (Necessity) if there exist a test satisfying 8.3.1 and 8.3.2 with k . . . .. . . .. . .. . . . .. . . .. . . Neyman-Pearson Lemma . Theorem 8.3.12 - Neyman-Pearson Lemma satisfying Pr X March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . A Pr X A test satisfies 8.3.1 except perhaps on a set A . every UMP level test (satisfies 8.3.2), and test is a size then every UMP level , test R that satisfies . .. .. . . .. . .. . . .. . .. . . . .. . . .. . . .. . . . . . .. . . .. . . .. . . .. . .. .. . . 9 / 1 Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where the pdf or pmf corresponding the θ i is f ( x | θ i ) , i = 0 , 1 , using a test with rejection region x ∈ R if f ( x | θ 1 ) > kf ( x | θ 0 ) (8 . 3 . 1) and x ∈ R c if f ( x | θ 1 ) < kf ( x | θ 0 ) (8 . 3 . 2) For some k ≥ 0 and α = Pr ( X ∈ R | θ 0 ) , Then, • (Sufficiency) Any test that satisfies 8.3.1 and 8.3.2 is a UMP level α

  18. . . . . .. . . .. . . .. .. . .. . . .. . . . March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang test R that satisfies . Theorem 8.3.12 - Neyman-Pearson Lemma .. . Neyman-Pearson Lemma . .. . . .. . . . . . .. . .. .. . . .. . . .. . . .. . . .. . . .. . .. . 9 / 1 . . .. . . . .. . Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where the pdf or pmf corresponding the θ i is f ( x | θ i ) , i = 0 , 1 , using a test with rejection region x ∈ R if f ( x | θ 1 ) > kf ( x | θ 0 ) (8 . 3 . 1) and x ∈ R c if f ( x | θ 1 ) < kf ( x | θ 0 ) (8 . 3 . 2) For some k ≥ 0 and α = Pr ( X ∈ R | θ 0 ) , Then, • (Sufficiency) Any test that satisfies 8.3.1 and 8.3.2 is a UMP level α • (Necessity) if there exist a test satisfying 8.3.1 and 8.3.2 with k > 0 , then every UMP level α test is a size α test (satisfies 8.3.2), and every UMP level α test satisfies 8.3.1 except perhaps on a set A satisfying Pr ( X ∈ A | θ 0 ) = Pr ( X ∈ A | θ 1 ) = 0 .

  19. • Suppose that k • Suppose that . f f f Calculating the ratios of the pmfs given, . vs. H H Example of Neyman-Pearson Lemma . f . . .. . . .. . . .. .. f f rejects H if x March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang Pr x Pr x Pr reject . or x test .. , and UMP level , then R k . Pr reject H test always rejects H . Therefore UMP level , and , then the rejection region R . . .. . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . . . .. . . .. . . .. . .. .. . . .. . . .. . . 10 / 1 Let X ∈ Binomial (2 , θ ) , and consider testing

  20. • Suppose that k • Suppose that .. f f f f Calculating the ratios of the pmfs given, Example of Neyman-Pearson Lemma . . f . .. . . .. . . .. . f . .. rejects H if x March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang Pr x Pr x Pr reject . or x test , then the rejection region R , and UMP level , then R k . Pr reject H test always rejects H . Therefore UMP level , and . .. . . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. .. . . .. . . .. . . . .. . .. . . .. . . 10 / 1 Let X ∈ Binomial (2 , θ ) , and consider testing H 0 : θ = θ 0 = 1/2 vs. H 1 : θ = θ 1 = 3/4 .

  21. • Suppose that k • Suppose that . Example of Neyman-Pearson Lemma . .. . . .. . . .. . . .. . .. .. . Calculating the ratios of the pmfs given, , and , then the rejection region R or x March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang Pr x Pr x Pr reject . rejects H if x .. test , and UMP level , then R k . Pr reject H test always rejects H . Therefore UMP level . . . . . . .. . . .. . . .. . . .. . . .. . . .. . . .. 10 / 1 . .. . .. . . .. . . .. . .. . . . . .. . Let X ∈ Binomial (2 , θ ) , and consider testing H 0 : θ = θ 0 = 1/2 vs. H 1 : θ = θ 1 = 3/4 . f (0 | θ 1 ) f (1 | θ 1 ) f (2 | θ 1 ) f (0 | θ 0 ) = 1 f (1 | θ 0 ) = 3 f (2 | θ 0 ) = 9 4 , 4 , 4

  22. • Suppose that . .. .. . . .. . . . . . .. .. . .. . . . .. . . March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang Pr x Pr x Pr reject or x . rejects H if x test , and UMP level , then R k Calculating the ratios of the pmfs given, Example of Neyman-Pearson Lemma .. . . .. .. .. . . .. . . . . . .. . . .. . . . 10 / 1 .. . . . .. . . . . .. . .. . .. . . .. . Let X ∈ Binomial (2 , θ ) , and consider testing H 0 : θ = θ 0 = 1/2 vs. H 1 : θ = θ 1 = 3/4 . f (0 | θ 1 ) f (1 | θ 1 ) f (2 | θ 1 ) f (0 | θ 0 ) = 1 f (1 | θ 0 ) = 3 f (2 | θ 0 ) = 9 4 , 4 , 4 • Suppose that k < 1/4 , then the rejection region R = { 0 , 1 , 2 } , and UMP level α test always rejects H 0 . Therefore α = Pr ( reject H 0 | θ = θ 0 = 1/2) = 1 .

  23. . . .. . . .. . .. .. . . .. . . .. . .. . Calculating the ratios of the pmfs given, March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang Pr x Pr x Pr reject Example of Neyman-Pearson Lemma . . .. . . .. . . . .. .. . . .. . . .. . . .. . . .. . . . . . . .. . . .. . . 10 / 1 . .. .. . . .. . Let X ∈ Binomial (2 , θ ) , and consider testing H 0 : θ = θ 0 = 1/2 vs. H 1 : θ = θ 1 = 3/4 . f (0 | θ 1 ) f (1 | θ 1 ) f (2 | θ 1 ) f (0 | θ 0 ) = 1 f (1 | θ 0 ) = 3 f (2 | θ 0 ) = 9 4 , 4 , 4 • Suppose that k < 1/4 , then the rejection region R = { 0 , 1 , 2 } , and UMP level α test always rejects H 0 . Therefore α = Pr ( reject H 0 | θ = θ 0 = 1/2) = 1 . • Suppose that 1/4 < k < 3/4 , then R = { 1 , 2 } , and UMP level α test rejects H 0 if x = 1 or x = 2 .

  24. . .. . .. . . .. . .. .. . . .. . . . .. . .. . . .. . . .. . Example of Neyman-Pearson Lemma Calculating the ratios of the pmfs given, Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . . . .. . . .. . . .. . . .. . . .. . . . . . .. . . . .. . 10 / 1 .. . . .. . .. . Let X ∈ Binomial (2 , θ ) , and consider testing H 0 : θ = θ 0 = 1/2 vs. H 1 : θ = θ 1 = 3/4 . f (0 | θ 1 ) f (1 | θ 1 ) f (2 | θ 1 ) f (0 | θ 0 ) = 1 f (1 | θ 0 ) = 3 f (2 | θ 0 ) = 9 4 , 4 , 4 • Suppose that k < 1/4 , then the rejection region R = { 0 , 1 , 2 } , and UMP level α test always rejects H 0 . Therefore α = Pr ( reject H 0 | θ = θ 0 = 1/2) = 1 . • Suppose that 1/4 < k < 3/4 , then R = { 1 , 2 } , and UMP level α test rejects H 0 if x = 1 or x = 2 . α = Pr ( reject | θ = 1/2) = Pr ( x = 1 | θ = 1/2) + Pr ( x = 2 | θ = 1/2) = 3 4

  25. • If k . . . .. . . .. .. . .. . . .. . . . . .. . .. . . .. . Example of Neyman-Pearson Lemma (cont’d) Pr reject Pr x the UMP level test always not reject H , and Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 .. . . . . . .. . . .. . .. .. . . .. . . .. . . . . . .. . . .. . 11 / 1 .. .. . . .. . . • Suppose that 3/4 < k < 9/4 , then UMP level α test rejects H 0 if x = 2

  26. • If k . . .. . . .. . . .. . . .. . . .. .. . . . . .. . . .. . Example of Neyman-Pearson Lemma (cont’d) the UMP level test always not reject H , and Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 .. . .. .. . . .. . . .. . . .. . . .. . . . . . . .. . . .. . 11 / 1 . .. . . .. . . .. • Suppose that 3/4 < k < 9/4 , then UMP level α test rejects H 0 if x = 2 α = Pr ( reject | θ = 1/2) = Pr ( x = 2 | θ = 1/2) = 1 4

  27. . . .. . .. . . .. . . .. . . .. . .. . . . .. . . .. . . .. . Example of Neyman-Pearson Lemma (cont’d) Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 .. . . . . . .. . . .. . . .. . . .. .. . .. .. . . .. . . . . . .. . . .. . 11 / 1 • Suppose that 3/4 < k < 9/4 , then UMP level α test rejects H 0 if x = 2 α = Pr ( reject | θ = 1/2) = Pr ( x = 2 | θ = 1/2) = 1 4 • If k > 9/4 the UMP level α test always not reject H 0 , and α = 0

  28. . n x i i n exp f x f x x i exp i f x n i.i.d. X i Example - Normal Distribution . .. . . .. . . exp i .. n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang x i i n n exp x i i x i x i i n exp x i i n x i i n exp .. . . .. . .. . . .. . . .. . . . .. . .. . . .. . . .. . . . . .. . . . .. . . .. . . .. . 12 / 1 . .. . . .. . . .. . . .. ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 .

  29. . X i exp x i i n exp f x f x n i.i.d. Example - Normal Distribution i . .. . . .. . . .. . n x i .. i March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang x i i n n exp x i n exp x i i n exp x i i n x i i n . .. . .. .. . . .. . . .. . . .. . . . . . .. . . .. . . .. . . .. . . . .. . . .. . . .. . . .. . . .. . . 12 / 1 .. . ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . − ( x i − θ ) 2 [ 1 { }] ∏ f ( x | θ ) = 2 πσ 2 exp 2 σ 2 i =1

  30. . . exp n i.i.d. X i Example - Normal Distribution . .. . .. exp . . .. . . .. . . exp n . x i March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang x i i n n exp i i n x i i n exp x i i n x i .. .. . . . . .. . . .. . . .. . .. .. . . .. . . .. . . .. . . .. 12 / 1 . . . . .. . .. . . .. . .. . . . . .. ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . − ( x i − θ ) 2 [ 1 { }] ∏ f ( x | θ ) = 2 πσ 2 exp 2 σ 2 i =1 { ∑ n i =1 ( x i − θ 1 ) 2 } − f ( x | θ 1 ) 2 σ 2 = { } f ( x | θ 0 ) ∑ n i =1 ( x i − θ 0 ) 2 − 2 σ 2

  31. . . Example - Normal Distribution . .. . . .. . .. i.i.d. . . .. . . .. . . .. n . exp March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang x i i n n x i exp i n x i i n exp exp exp .. X i . . .. . . .. . . .. . .. . . . .. . . .. . . .. 12 / 1 . . . .. . . . .. . . .. . . . .. .. .. . . ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . − ( x i − θ ) 2 [ 1 { }] ∏ f ( x | θ ) = 2 πσ 2 exp 2 σ 2 i =1 { ∑ n i =1 ( x i − θ 1 ) 2 } − f ( x | θ 1 ) 2 σ 2 = { } f ( x | θ 0 ) ∑ n i =1 ( x i − θ 0 ) 2 − 2 σ 2 i =1 ( x i − θ 1 ) 2 i =1 ( x i − θ 0 ) 2 [ ∑ n ∑ n ] − = + 2 σ 2 2 σ 2

  32. . .. .. . . .. . . . . . .. . . .. . . . .. . exp March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang x i i n n exp . exp exp exp n i.i.d. .. Example - Normal Distribution .. X i . .. .. . . .. . . . . . .. . . .. . . . .. .. .. . . .. . . .. . . .. . . . 12 / 1 . . . .. ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . − ( x i − θ ) 2 [ 1 { }] ∏ f ( x | θ ) = 2 πσ 2 exp 2 σ 2 i =1 { ∑ n i =1 ( x i − θ 1 ) 2 } − f ( x | θ 1 ) 2 σ 2 = { } f ( x | θ 0 ) ∑ n i =1 ( x i − θ 0 ) 2 − 2 σ 2 i =1 ( x i − θ 1 ) 2 i =1 ( x i − θ 0 ) 2 [ ∑ n ∑ n ] − = + 2 σ 2 2 σ 2 i =1 ( x i − θ 0 ) 2 − ∑ n i =1 ( x i − θ 1 ) 2 [∑ n ] = 2 σ 2

  33. . .. .. . . .. . . . . . .. . . .. . . .. .. exp March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang exp exp exp exp . n .. X i Example - Normal Distribution . .. . . i.i.d. . . . . .. . . .. . . .. . . .. . . .. . . . .. . . .. . . .. .. . 12 / 1 .. . . .. . . ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . − ( x i − θ ) 2 [ 1 { }] ∏ f ( x | θ ) = 2 πσ 2 exp 2 σ 2 i =1 { ∑ n i =1 ( x i − θ 1 ) 2 } − f ( x | θ 1 ) 2 σ 2 = { } f ( x | θ 0 ) ∑ n i =1 ( x i − θ 0 ) 2 − 2 σ 2 i =1 ( x i − θ 1 ) 2 i =1 ( x i − θ 0 ) 2 [ ∑ n ∑ n ] − = + 2 σ 2 2 σ 2 i =1 ( x i − θ 0 ) 2 − ∑ n i =1 ( x i − θ 1 ) 2 [∑ n ] = 2 σ 2 0 − θ 1 ) 2 + 2 ∑ n [ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ] = 2 σ 2

  34. . . .. . . .. . . .. . Example (cont’d) .. . . .. . . .. . exp . Pr March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k X i i n k n x i i n log k x i i n . .. .. . . . .. . . .. . .. .. . . .. . . .. . . . 13 / 1 . . .. . . .. . . .. . . .. .. . . .. . . . UMP level α test rejects if 0 − θ 1 ) 2 + 2 ∑ n [ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ] > k 2 σ 2

  35. . . . . .. . . .. . . .. . .. .. . . .. .. . . n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k X i i Pr .. k x i i n exp Example (cont’d) . . . .. .. . . . .. . . . . . .. . . .. . . .. 13 / 1 . . . . .. .. . . .. . . .. . . .. . . .. UMP level α test rejects if 0 − θ 1 ) 2 + 2 ∑ n [ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ] > k 2 σ 2 0 − θ 1 ) 2 + 2 ∑ n ⇒ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ⇐ > log k 2 σ 2

  36. . .. .. . . .. . . .. . . .. . . .. . . .. .. n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k X i i Pr . n exp Example (cont’d) . .. . . . . .. . . .. . . . . . . .. . . .. . . .. 13 / 1 . .. .. .. . . .. . . . . .. . . .. . . UMP level α test rejects if 0 − θ 1 ) 2 + 2 ∑ n [ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ] > k 2 σ 2 0 − θ 1 ) 2 + 2 ∑ n ⇒ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ⇐ > log k 2 σ 2 ∑ x i > k ∗ ⇐ ⇒ i =1

  37. . . .. . . .. . . .. . . .. . . .. . .. . . . .. . . .. . Example (cont’d) exp n Pr Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . .. .. . . .. . . .. . .. .. . . . .. . . . 13 / 1 . . . . .. . . . .. .. . . .. . . .. UMP level α test rejects if 0 − θ 1 ) 2 + 2 ∑ n [ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ] > k 2 σ 2 0 − θ 1 ) 2 + 2 ∑ n ⇒ n ( θ 2 i =1 x i ( θ 1 − θ 0 ) ⇐ > log k 2 σ 2 ∑ x i > k ∗ ⇐ ⇒ i =1 ( n ) ∑ X i > k ∗ | θ 0 α = i =1

  38. . .. . .. . . .. . . . X i . .. . . .. . . Example (cont’d) X .. k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . where Z n n Z n Pr k X i i n Pr n X .. . . . .. . . .. . . .. . .. .. . . .. . . .. . . . 14 / 1 . .. . . .. . . .. . . . . .. . . .. . . .. Under H 0 , N ( θ 0 , σ 2 ) ∼

  39. . . .. . . .. . . .. . Example (cont’d) .. . . .. . . .. . X i . k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . where Z n n Z X Pr k X i i n Pr n X . .. .. . . . .. . . .. . .. . . . .. . . .. . . .. 14 / 1 . . . .. . . .. . . .. . .. . . .. . . .. . Under H 0 , N ( θ 0 , σ 2 ) ∼ N ( θ 0 , σ 2 / n ) ∼

  40. . . . . .. . . .. . .. . . . .. . .. .. . .. Example (cont’d) .. k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . where Z n n Z X i Pr k X i i n Pr X . . . .. . .. . . .. . . . . . .. . . .. . . . 14 / 1 .. . .. . . .. . . .. . . .. . .. . . .. . . Under H 0 , N ( θ 0 , σ 2 ) ∼ N ( θ 0 , σ 2 / n ) ∼ X − θ 0 σ / √ n ∼ N (0 , 1)

  41. . . .. . . .. . . .. . .. .. . . .. . .. . X i March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang Pr Pr X Example (cont’d) . . .. . . .. . . . .. . . .. . . .. . . .. .. . . .. . . . 14 / 1 . . . . .. . . . .. . . .. . . .. .. Under H 0 , N ( θ 0 , σ 2 ) ∼ N ( θ 0 , σ 2 / n ) ∼ X − θ 0 σ / √ n ∼ N (0 , 1) ( n ) ∑ X i > k ∗ | θ 0 = α i =1 Z > k ∗ / n − θ 0 ( ) σ / √ n = where Z ∼ N (0 , 1) .

  42. if X .. . .. . . .. . . . .. . . .. . . .. . . . .. k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang n z n k , or equivalently, reject H Example (cont’d) X i test reject if Thus, the UMP level n z n k .. . . .. . .. . . .. . . . .. . .. . . .. . . . . . .. .. . . .. . . .. . . . . . .. . . .. 15 / 1 k ∗ / n − θ 0 σ / √ n = z α

  43. . . . . .. . . .. . . .. . . .. . . .. .. . . k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang n z n if X .. k , or equivalently, reject H X i test reject if Thus, the UMP level n Example (cont’d) . . .. .. .. . . . .. . . . . . .. . . .. . . .. 15 / 1 . . .. . .. .. . . .. . . . .. . .. . . . k ∗ / n − θ 0 σ / √ n = z α ( ) σ k ∗ √ n = θ 0 + z α

  44. . .. . .. . .. .. . . .. . . .. . . . .. . .. . . .. . . .. . Example (cont’d) n Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . . . .. . . .. . . .. . . . . . .. . . .. . . .. . . .. . . 15 / 1 .. . . .. . .. . k ∗ / n − θ 0 σ / √ n = z α ( ) σ k ∗ √ n = θ 0 + z α Thus, the UMP level α test reject if ∑ X i > k ∗ , or equivalently, reject H 0 if X > k ∗ / n = θ 0 + z α σ / √ n

  45. . . Neyman-Pearson Lemma on Sufficient Statistics . .. . . .. . .. Corollary 8.3.13 . . .. . . .. . . . . . k g t March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T and For some k if g t . S c t and k g t if g t S t satisfies .. .. . . . . .. . . .. . .. . . . .. . . .. . . .. .. . . . . .. . . .. . . .. . .. .. . . .. . . 16 / 1 Consider H 0 : θ = θ 0 vs H 1 : θ = θ 1 . Suppose T ( X ) is a sufficient statistic for θ and g ( t | θ i ) is the pdf or pmf of T . Corresponding θ i , i ∈ { 0 , 1 } . Then any test based on T with rejection region S is a UMP level α test if it

  46. . . . .. . . .. . .. .. . . .. . . .. . . . .. k g t March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T and For some k if g t Neyman-Pearson Lemma on Sufficient Statistics S c t satisfies . . Corollary 8.3.13 . .. . . .. . .. . . .. . . . .. . .. . . .. . . . . . .. .. . . .. . . .. . . . . . .. . . .. 16 / 1 Consider H 0 : θ = θ 0 vs H 1 : θ = θ 1 . Suppose T ( X ) is a sufficient statistic for θ and g ( t | θ i ) is the pdf or pmf of T . Corresponding θ i , i ∈ { 0 , 1 } . Then any test based on T with rejection region S is a UMP level α test if it t ∈ S if g ( t | θ 1 ) > k · g ( t | θ 0 ) and

  47. . . . .. . . .. . .. .. . . .. . . .. . . . For some k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T and satisfies . . . Corollary 8.3.13 . Neyman-Pearson Lemma on Sufficient Statistics . .. . .. .. .. .. . . .. . . . . . .. . . .. . . . . .. . . .. . . .. . . .. . . .. . . .. . 16 / 1 Consider H 0 : θ = θ 0 vs H 1 : θ = θ 1 . Suppose T ( X ) is a sufficient statistic for θ and g ( t | θ i ) is the pdf or pmf of T . Corresponding θ i , i ∈ { 0 , 1 } . Then any test based on T with rejection region S is a UMP level α test if it t ∈ S if g ( t | θ 1 ) > k · g ( t | θ 0 ) and t ∈ S c if g ( t | θ 1 ) < k · g ( t | θ 0 )

  48. . .. . .. .. . . .. . . .. . . .. . . . . Corollary 8.3.13 March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang satisfies . . . . Neyman-Pearson Lemma on Sufficient Statistics . .. . . .. .. . . . . .. .. . . .. . . .. . . .. . . .. . . .. . . .. . .. . 16 / 1 . . .. . . .. . . Consider H 0 : θ = θ 0 vs H 1 : θ = θ 1 . Suppose T ( X ) is a sufficient statistic for θ and g ( t | θ i ) is the pdf or pmf of T . Corresponding θ i , i ∈ { 0 , 1 } . Then any test based on T with rejection region S is a UMP level α test if it t ∈ S if g ( t | θ 1 ) > k · g ( t | θ 0 ) and t ∈ S c if g ( t | θ 1 ) < k · g ( t | θ 0 ) For some k > 0 and α = Pr ( T ∈ S | θ 0 )

  49. . . kg T x g T x x R The rejection region in the sample space is Proof . .. . f x .. . . .. . . .. . By Factorization Theorem: i .. By Neyman-Pearson Lemma, this test is the UMP level March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T X R Pr X test, and kf x h x g T x f x x h x kg T x h x g T x x R i . .. . . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. .. . . .. . . .. . . . .. . .. . . .. . . 17 / 1 = { x : T ( x ) = t ∈ S }

  50. . .. By Factorization Theorem: R The rejection region in the sample space is Proof . .. . . . i . .. . . .. . . .. f x h x g T x . By Neyman-Pearson Lemma, this test is the UMP level March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T X R Pr X test, and kf x i f x x h x kg T x h x g T x x R .. . .. . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . . . .. . . .. . . .. . .. . . .. . . .. 17 / 1 = { x : T ( x ) = t ∈ S } = { x : g ( T ( x ) | θ 1 ) > kg ( T ( x ) | θ 0 ) }

  51. . . Proof . .. . . .. . .. R . . .. . . .. .. . The rejection region in the sample space is By Factorization Theorem: . test, and March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T X R Pr X By Neyman-Pearson Lemma, this test is the UMP level R kf x f x x h x kg T x h x g T x x .. . . . .. . . .. . . .. . .. .. . . .. . . .. . . . 17 / 1 .. . . . .. . . . . .. . . . .. .. . . . .. = { x : T ( x ) = t ∈ S } = { x : g ( T ( x ) | θ 1 ) > kg ( T ( x ) | θ 0 ) } f ( x | θ i ) = h ( x ) g ( T ( x ) | θ i )

  52. . . . .. . . .. . .. .. . . .. . . .. . . . .. test, and March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T X R Pr X By Neyman-Pearson Lemma, this test is the UMP level Proof kf x f x x R By Factorization Theorem: R The rejection region in the sample space is . .. . .. .. . . . .. . . . . . .. . . .. . . . 17 / 1 .. . .. . . . .. .. . .. . . . . .. . .. . . = { x : T ( x ) = t ∈ S } = { x : g ( T ( x ) | θ 1 ) > kg ( T ( x ) | θ 0 ) } f ( x | θ i ) = h ( x ) g ( T ( x ) | θ i ) = { x : g ( T ( x ) | θ 1 ) h ( x ) > kg ( T ( x ) | θ 0 ) h ( x ) }

  53. . . . . .. . . .. . . .. . . .. . . .. .. . . Pr X March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang S Pr T X R test, and .. By Neyman-Pearson Lemma, this test is the UMP level R By Factorization Theorem: R The rejection region in the sample space is Proof . . .. .. .. .. . . . . . . . . .. . . .. . . . .. .. . . .. . . .. . . .. . . 17 / 1 . .. . . .. = { x : T ( x ) = t ∈ S } = { x : g ( T ( x ) | θ 1 ) > kg ( T ( x ) | θ 0 ) } f ( x | θ i ) = h ( x ) g ( T ( x ) | θ i ) = { x : g ( T ( x ) | θ 1 ) h ( x ) > kg ( T ( x ) | θ 0 ) h ( x ) } = { x : f ( x | θ 1 ) > kf ( x | θ 0 ) }

  54. . . .. . . .. . .. .. . . .. . . .. . .. . The rejection region in the sample space is March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang R By Factorization Theorem: R Proof . . .. . . .. . . . .. .. . . .. . . .. . . . . . .. . . .. . . . .. . . . .. 17 / 1 . . . . .. . .. .. = { x : T ( x ) = t ∈ S } = { x : g ( T ( x ) | θ 1 ) > kg ( T ( x ) | θ 0 ) } f ( x | θ i ) = h ( x ) g ( T ( x ) | θ i ) = { x : g ( T ( x ) | θ 1 ) h ( x ) > kg ( T ( x ) | θ 0 ) h ( x ) } = { x : f ( x | θ 1 ) > kf ( x | θ 0 ) } By Neyman-Pearson Lemma, this test is the UMP level α test, and = Pr ( X ∈ R ) = Pr ( T ( X ) ∈ S | θ 0 ) α

  55. . . g t n . , where T X is a sufficient statistic for T i.i.d. X i Revisiting the Example of Normal Distribution .. n . . .. . . .. . . .. i exp .. exp March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang t n exp t t n n t t exp n t exp g t g t n i . . .. . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . . . .. . . .. . . .. . .. .. . . .. . . .. . . 18 / 1 ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 .

  56. . . i g t i.i.d. X i Revisiting the Example of Normal Distribution . .. . .. exp . . .. . . .. . . n t . n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang t n exp t t exp i n t exp n t exp g t g t n .. .. . . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . .. . . . .. . . .. . . .. . .. .. . . .. . . 18 / 1 ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . T = X is a sufficient statistic for θ , where T ∼ N ( θ, σ 2 / n ) .

  57. . . Revisiting the Example of Normal Distribution . .. . . .. . .. i.i.d. . . .. . .. .. . . X i exp . t March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang t n exp t n g t exp n t exp n t exp g t .. . . . .. . . .. . . .. . .. .. . . .. . . .. . . . 18 / 1 .. . .. . . .. . . .. . . .. . . . .. . . . ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . T = X is a sufficient statistic for θ , where T ∼ N ( θ, σ 2 / n ) . − ( t − θ i ) 2 1 { } g ( t | θ i ) = 2 σ 2 / n √ 2 πσ 2 / n

  58. . .. .. . . .. . .. . . . .. . . .. . . . .. . t March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang t n exp t n . exp exp exp exp i.i.d. X i Revisiting the Example of Normal Distribution .. . . .. .. . .. . .. . . . . . .. . . .. . . . 18 / 1 .. . . . .. . . .. . . .. . . .. . . .. . ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . T = X is a sufficient statistic for θ , where T ∼ N ( θ, σ 2 / n ) . − ( t − θ i ) 2 1 { } g ( t | θ i ) = 2 σ 2 / n √ 2 πσ 2 / n { } − ( t − θ 1 ) 2 g ( t | θ 1 ) 2 σ 2 / n = g ( t | θ 0 ) { } − ( t − θ 0 ) 2 2 σ 2 / n

  59. . . . .. . . .. . .. .. . . .. . . .. . . . exp March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang t n exp exp . exp exp i.i.d. X i Revisiting the Example of Normal Distribution . .. . .. .. .. . . .. . . . . . . .. . . .. . . .. 18 / 1 . . . .. . .. . . .. . . .. .. . . .. . . ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . T = X is a sufficient statistic for θ , where T ∼ N ( θ, σ 2 / n ) . − ( t − θ i ) 2 1 { } g ( t | θ i ) = 2 σ 2 / n √ 2 πσ 2 / n { } − ( t − θ 1 ) 2 g ( t | θ 1 ) 2 σ 2 / n = g ( t | θ 0 ) { } − ( t − θ 0 ) 2 2 σ 2 / n { 1 ( t − θ 1 ) 2 − ( t − θ 0 ) 2 ]} [ = − 2 σ 2 / n

  60. . .. .. . . .. . . . . . .. . . .. . . .. .. exp March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang exp exp exp exp .. i.i.d. X i Revisiting the Example of Normal Distribution . .. . . . . . . . .. . . .. . . . .. . . .. . . .. 18 / 1 . .. .. . .. . . . . .. . . .. . .. . . ∼ N ( θ, σ 2 ) where σ 2 is known. Consider testing H 0 : θ = θ 0 vs. H 1 : θ = θ 1 where θ 1 > θ 0 . T = X is a sufficient statistic for θ , where T ∼ N ( θ, σ 2 / n ) . − ( t − θ i ) 2 1 { } g ( t | θ i ) = 2 σ 2 / n √ 2 πσ 2 / n { } − ( t − θ 1 ) 2 g ( t | θ 1 ) 2 σ 2 / n = g ( t | θ 0 ) { } − ( t − θ 0 ) 2 2 σ 2 / n { 1 ( t − θ 1 ) 2 − ( t − θ 0 ) 2 ]} [ = − 2 σ 2 / n { 1 ]} θ 2 1 − θ 2 [ = − 0 − 2 t ( θ 1 − θ 0 ) 2 σ 2 / n

  61. . .. .. . . .. . . . . . .. .. . .. . . .. .. log k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k t X t . n k exp Revisiting the Example (cont’d) . .. . . . . . . . . . . .. . . .. . . .. . . .. .. . .. .. . . .. . . .. . . .. 19 / 1 . . .. . . UMP level α test reject if { 1 ]} θ 2 1 − θ 2 [ − 0 − 2 t ( θ 1 − θ 0 ) > 2 σ 2 / n

  62. . . . . .. . . .. . . .. . . .. . . .. . . log k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k t X k .. exp Revisiting the Example (cont’d) . .. . . .. .. . . . .. . . .. .. . .. .. . . .. . . . 19 / 1 . . . . .. . . .. . . .. .. . . .. . . UMP level α test reject if { 1 ]} θ 2 1 − θ 2 [ − 0 − 2 t ( θ 1 − θ 0 ) > 2 σ 2 / n 1 − ( θ 2 1 − θ 2 [ ] ⇐ ⇒ 0 ) + 2 t ( θ 1 − θ 0 ) > 2 σ 2 / n

  63. . . .. . . .. . . .. . . .. . . .. . .. . . . .. . . .. . Revisiting the Example (cont’d) exp k log k Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . .. .. . . .. . . .. . .. .. . . . .. . . . 19 / 1 . . . . .. . . .. . . . .. . . .. .. UMP level α test reject if { 1 ]} θ 2 1 − θ 2 [ − 0 − 2 t ( θ 1 − θ 0 ) > 2 σ 2 / n 1 − ( θ 2 1 − θ 2 [ ] ⇐ ⇒ 0 ) + 2 t ( θ 1 − θ 0 ) > 2 σ 2 / n k ∗ ⇐ ⇒ X = t >

  64. Pr X z n .. . .. . . .. . . . Pr reject H . .. . . .. . . Revisiting the Example (cont’d) . . n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k z n k k k Z Pr n k n X Pr .. . .. . . . .. . . .. . .. . . . .. . . .. . . .. . .. .. . . .. . . .. . . . . .. . . .. . . .. 20 / 1 Under H 0 , X ∼ N ( θ 0 , σ 2 / n ) . k ∗ satisfies

  65. z n . . .. . . .. . . .. . Revisiting the Example (cont’d) .. . . .. . . .. . Pr X . n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k z n k k k Z Pr n k n X Pr .. . .. . .. . . .. . . .. . .. . . . .. . . .. . . . 20 / 1 . .. . .. . . .. . . . .. . .. . . .. . . Under H 0 , X ∼ N ( θ 0 , σ 2 / n ) . k ∗ satisfies Pr ( reject H 0 | θ 0 ) = α

  66. z n . . . .. . . .. . . .. .. . .. . . .. . . Revisiting the Example (cont’d) . n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k z n k k .. Z Pr n k n X Pr . .. . .. . .. . . .. . . . . . .. . . .. . . . 20 / 1 .. . .. . . .. . . .. . . .. . .. . . .. . . Under H 0 , X ∼ N ( θ 0 , σ 2 / n ) . k ∗ satisfies Pr ( reject H 0 | θ 0 ) = α Pr ( X > k ∗ | θ 0 ) α =

  67. z n . . . .. . . .. . .. .. . . .. . . .. . . . k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k z n n . k Z Pr Pr Revisiting the Example (cont’d) . .. . .. .. .. . . . .. . . . . . .. . . .. . . .. 20 / 1 . .. . . .. .. . . . . . . .. . .. . . .. Under H 0 , X ∼ N ( θ 0 , σ 2 / n ) . k ∗ satisfies Pr ( reject H 0 | θ 0 ) = α Pr ( X > k ∗ | θ 0 ) α = σ / √ n > k ∗ − θ 0 ( X − θ 0 ) σ / √ n =

  68. z n . .. . . .. . . .. . . .. . . .. . .. .. . k March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang k z n Pr .. Pr Revisiting the Example (cont’d) . .. . . . . . .. . . .. . . . . . . .. . . .. . . .. 20 / 1 . . . .. .. . . .. . . .. . . .. . . .. Under H 0 , X ∼ N ( θ 0 , σ 2 / n ) . k ∗ satisfies Pr ( reject H 0 | θ 0 ) = α Pr ( X > k ∗ | θ 0 ) α = σ / √ n > k ∗ − θ 0 ( X − θ 0 ) σ / √ n = Z > k ∗ − θ 0 ( ) σ / √ n =

  69. z n . . .. . . .. .. . .. . . .. . . .. . .. . . . .. . . .. . Revisiting the Example (cont’d) Pr Pr k Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . . .. . . .. . . .. . . .. .. . . .. . . . 20 / 1 . .. . .. . . .. . . . . . .. . . .. Under H 0 , X ∼ N ( θ 0 , σ 2 / n ) . k ∗ satisfies Pr ( reject H 0 | θ 0 ) = α Pr ( X > k ∗ | θ 0 ) α = σ / √ n > k ∗ − θ 0 ( X − θ 0 ) σ / √ n = Z > k ∗ − θ 0 ( ) σ / √ n = k ∗ − θ 0 σ / √ n = z α

  70. . . .. . . .. . . .. . . .. . . .. . .. . . . .. . . .. . Revisiting the Example (cont’d) Pr Pr n Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 . .. .. . . .. . . .. . . .. .. . . .. . . . 20 / 1 . . .. . . .. . . . .. . . .. . . .. Under H 0 , X ∼ N ( θ 0 , σ 2 / n ) . k ∗ satisfies Pr ( reject H 0 | θ 0 ) = α Pr ( X > k ∗ | θ 0 ) α = σ / √ n > k ∗ − θ 0 ( X − θ 0 ) σ / √ n = Z > k ∗ − θ 0 ( ) σ / √ n = k ∗ − θ 0 σ / √ n = z α σ k ∗ = θ 0 + z α

  71. . . . . .. . . .. . . .. . . .. . .. .. . . . March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang theorems are stated according to the definition. Note: we may define MLR using decreasing function of t . But all following . Definition .. . Monotone Likelihood Ratio . .. . . .. . . . .. . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. 21 / 1 . . .. . . .. . . A family of pdfs or pmfs { g ( t | θ ) : θ ∈ Ω } for a univariate random variable T with real-valued parameter θ have a monotone likelihood ratio if g ( t | θ 2 ) g ( t | θ 1 ) is an increasing (or non-decreasing) function of t for every θ 2 > θ 1 on { t : g ( t | θ 1 ) > 0 or g ( t | θ 2 ) > 0 } .

  72. . . . . .. . . .. . . .. . . .. . .. .. . . . March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang theorems are stated according to the definition. Note: we may define MLR using decreasing function of t . But all following . Definition .. . Monotone Likelihood Ratio . .. . . .. . . . .. . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. 21 / 1 . . .. . . .. . . A family of pdfs or pmfs { g ( t | θ ) : θ ∈ Ω } for a univariate random variable T with real-valued parameter θ have a monotone likelihood ratio if g ( t | θ 2 ) g ( t | θ 1 ) is an increasing (or non-decreasing) function of t for every θ 2 > θ 1 on { t : g ( t | θ 1 ) > 0 or g ( t | θ 2 ) > 0 } .

  73. • If T is from an exponential family with the pdf or pmf . . .. . . .. . .. . . . .. . . .. . . .. .. t March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . is a non-decreasing function of Then T has an MLR if w exp w . h t c g t Example of Monotone Likelihood Ratio . .. . . .. . . . . .. . . .. . . .. . . .. . . .. . . . .. . . .. . . .. . .. .. . . .. . . 22 / 1 • Normal, Poisson, Binomial have the MLR Property (Exercise 8.25)

  74. . . .. . .. . . .. . . .. . . .. . .. . . . .. . . .. . . .. . Example of Monotone Likelihood Ratio Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 .. . . . . . .. . . .. . . .. . . .. . .. .. .. . . .. . . . . . .. . . .. . 22 / 1 • Normal, Poisson, Binomial have the MLR Property (Exercise 8.25) • If T is from an exponential family with the pdf or pmf g ( t | θ ) = h ( t ) c ( θ ) exp [ w ( θ ) · t ] Then T has an MLR if w ( θ ) is a non-decreasing function of θ .

  75. t is an increasing function of t . Therefore, g t .. h t c t exp w h t c g t g t Proof . . t . . .. . . .. . . .. exp w c c g t March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . function of is a non-decreasing non-decreasing function of t , and T has MLR if w is a w . exp w and w , then w is a non-decreasing function of If w t w exp w . .. .. . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . . . .. . . .. . . .. . .. .. . . .. . . .. . . 23 / 1 Suppose that θ 2 > θ 1 .

  76. t is an increasing function of t . Therefore, g t . Proof . .. . . .. . . c .. . . .. . . .. .. c w exp w is a March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . function of is a non-decreasing non-decreasing function of t , and T has MLR if w g t .. w exp w and w , then w is a non-decreasing function of If w t . . . . . . .. . . .. . . .. . . .. . . .. . . .. . . .. 23 / 1 . .. .. . . .. . . .. . . . . .. . . .. . Suppose that θ 2 > θ 1 . g ( t | θ 2 ) h ( t ) c ( θ 2 ) exp [ w ( θ 2 ) t ] = g ( t | θ 1 ) h ( t ) c ( θ 1 ) exp [ w ( θ 1 ) t ]

  77. t is an increasing function of t . Therefore, g t . . . .. . . .. . .. .. . . .. . .. .. . . Proof . is a March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . function of is a non-decreasing non-decreasing function of t , and T has MLR if w g t .. w exp w and w , then w is a non-decreasing function of If w . . . .. . .. . . .. . . . . . .. . . .. . . . 23 / 1 .. . .. . . .. . . .. . . .. . .. . . .. . . Suppose that θ 2 > θ 1 . g ( t | θ 2 ) h ( t ) c ( θ 2 ) exp [ w ( θ 2 ) t ] = g ( t | θ 1 ) h ( t ) c ( θ 1 ) exp [ w ( θ 1 ) t ] c ( θ 2 ) = c ( θ 1 ) exp [ { w ( θ 2 ) − w ( θ 1 ) } t ]

  78. t is an increasing function of t . Therefore, g t . . . .. . . .. . .. .. . . .. .. . .. . . . non-decreasing function of t , and T has MLR if w March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . function of is a non-decreasing is a . g t w exp w Proof . .. . . .. .. .. . . .. . . . . . .. . . .. . . . . .. . . .. . . .. . . .. . . .. 23 / 1 . . .. . Suppose that θ 2 > θ 1 . g ( t | θ 2 ) h ( t ) c ( θ 2 ) exp [ w ( θ 2 ) t ] = g ( t | θ 1 ) h ( t ) c ( θ 1 ) exp [ w ( θ 1 ) t ] c ( θ 2 ) = c ( θ 1 ) exp [ { w ( θ 2 ) − w ( θ 1 ) } t ] If w ( θ ) is a non-decreasing function of θ , then w ( θ 2 ) − w ( θ 1 ) ≥ 0 and

  79. . . . . .. . .. .. . . .. . . .. . .. . . . .. . . .. . . .. . Proof Hyun Min Kang Biostatistics 602 - Lecture 20 March 28th, 2013 .. . . . . . .. . . .. . .. .. . . .. . . .. .. . . .. . . . 23 / 1 . . .. . . .. . Suppose that θ 2 > θ 1 . g ( t | θ 2 ) h ( t ) c ( θ 2 ) exp [ w ( θ 2 ) t ] = g ( t | θ 1 ) h ( t ) c ( θ 1 ) exp [ w ( θ 1 ) t ] c ( θ 2 ) = c ( θ 1 ) exp [ { w ( θ 2 ) − w ( θ 1 ) } t ] If w ( θ ) is a non-decreasing function of θ , then w ( θ 2 ) − w ( θ 1 ) ≥ 0 and exp [ { w ( θ 2 ) − w ( θ 1 ) } t ] is an increasing function of t . Therefore, g ( t | θ 2 ) g ( t | θ 1 ) is a non-decreasing function of t , and T has MLR if w ( θ ) is a non-decreasing function of θ .

  80. . . . . is an MLR family. Then . . Theorem 8.1.17 . Karlin-Rabin Theorem .. vs H . . .. . . .. . . .. 1 For testing H , the UMP level . test is given March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . t Pr T t where by rejecting H if and only if T , the UMP level test is given vs H 2 For testing H . . . t Pr T t where by rejecting H is and only if T . .. .. . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . . . .. . . .. . . .. . .. .. . . .. . . .. . . 24 / 1 Suppose T ( X ) is a sufficient statistic for θ and the family { g ( t | θ ) : θ ∈ Ω }

  81. . . Karlin-Rabin Theorem . .. . . .. . .. Theorem 8.1.17 . . .. . . .. . . . . . by rejecting H if and only if T March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . t Pr T t where test is given . , the UMP level vs H 2 For testing H . . . . is an MLR family. Then .. .. . . . . .. . . .. . .. . . . .. . . .. . . .. .. . . . . .. . . .. . . .. . .. .. . . .. . . 24 / 1 Suppose T ( X ) is a sufficient statistic for θ and the family { g ( t | θ ) : θ ∈ Ω } 1 For testing H 0 : θ ≤ θ 0 vs H 1 : θ > θ 0 , the UMP level α test is given by rejecting H 0 is and only if T > t 0 where α = Pr ( T > t 0 | θ 0 ) .

  82. . . . .. . . .. . .. .. . . .. . . .. . . . . March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang . . . is an MLR family. Then . . . Theorem 8.1.17 . Karlin-Rabin Theorem . .. .. . .. .. . . . .. . . . . . .. . . .. . . . .. .. .. . .. . . .. . . . . . .. . . .. . 24 / 1 Suppose T ( X ) is a sufficient statistic for θ and the family { g ( t | θ ) : θ ∈ Ω } 1 For testing H 0 : θ ≤ θ 0 vs H 1 : θ > θ 0 , the UMP level α test is given by rejecting H 0 is and only if T > t 0 where α = Pr ( T > t 0 | θ 0 ) . 2 For testing H 0 : θ ≥ θ 0 vs H 1 : θ < θ 0 , the UMP level α test is given by rejecting H 0 if and only if T < t 0 where α = Pr ( T < t 0 | θ 0 ) .

  83. n is an increasing function in . Let X i t exp n g t n . , and T X is a sufficient statistic for T X i.i.d. Example Application of Karlin-Rabin Theorem n . .. . . .. . . .. . n exp .. n March 28th, 2013 Biostatistics 602 - Lecture 20 Hyun Min Kang property. . Therefore T is MLR where w t exp w h t c t t exp n exp n t exp n n t . .. . .. .. . . .. . . .. . . . . . .. . . .. . . .. . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . 25 / 1 ∼ N ( θ, σ 2 ) where σ 2 is known, Find the UMP level α test for H 0 : θ ≤ θ 0 vs H 1 : θ > θ 0 .

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend


More recommend