Bounds on Deviation by Markov: Chebyshev Bound E[(R -) 2 ] x 2 - - PowerPoint PPT Presentation

bounds on deviation
SMART_READER_LITE
LIVE PREVIEW

Bounds on Deviation by Markov: Chebyshev Bound E[(R -) 2 ] x 2 - - PowerPoint PPT Presentation

Improving the Markov Bound Mathematics for Computer Science MIT 6.042J/18.062J Pr[|R| x] = Pr[(R) 2 x 2 ] Bounds on Deviation by Markov: Chebyshev Bound E[(R -) 2 ] x 2 variance of R chebyshev.1 chebyshev.2 Albert R


slide-1
SLIDE 1

chebyshev.1 Albert R Meyer, May 10, 2013

Bounds on Deviation

Chebyshev Bound

Mathematics for Computer Science

MIT 6.042J/18.062J

chebyshev.2 Albert R Meyer, May 10, 2013

Pr[|R−µ| ≥ x] = Pr[(R−µ)2 ≥ x2]

≤ E[(R -µ)2] x2

by Markov:

Improving the Markov Bound

variance of R

chebyshev.3 Albert R Meyer, May 10, 2013

Chebyshev Bound

Pr[|R -μ| ≥ x ] ≤ Var[R] x

2

Var[R] ::= E[(R - µ)2]

chebyshev.4 Albert R Meyer, May 10, 2013

Variance of a Random Variable

Variance is also called the

mean square error

Var[R] ::= E[(R - µ)2]

1

slide-2
SLIDE 2

chebyshev.5 Albert R Meyer, May 10, 2013

Pr[|R -μ| ≥ x ] ≤ Var[R] x

2

Chebyshev Bound

σ R ::= Var[R]

standard deviation

chebyshev.6 Albert R Meyer, May 10, 2013

σ R ::= Var[R]

standard deviation

Standard deviation is also called the

root mean square error

Standard Deviation of an RV

chebyshev.7 Albert R Meyer, May 10, 2013

σ R ::= Var[R]

μ

PDFR

σ R

  • Standard Deviation of an RV

chebyshev.8 Albert R Meyer, May 10, 2013

Pr[|R -μ| ≥ x ] ≤ σ R

2

x

2

Chebyshev Bound

σ R ::= Var[R]

2

slide-3
SLIDE 3

chebyshev.9 Albert R Meyer, May 10, 2013

Chebyshev Bound

σ R ::= Var[R]

Pr[|R -μ| ≥ x ] ≤ σ R

2

x

2

chebyshev.10 Albert R Meyer, May 10, 2013

Pr[|R -μ| ≥ cσ R ] ≤ 1 c

2

σ R ::= Var[R]

Chebyshev Bound (Restated)

chebyshev.11 Albert R Meyer, May 10, 2013

Pr[|R - μ| ≥ cσ R ] ≤ 1 c2

R probably not many σ’s from μ:

further than σ Pr ≤ 1 2σ Pr ≤ 1/4 3σ Pr ≤ 1/9 4σ Pr ≤ 1/16

Standard Deviation

3

slide-4
SLIDE 4

MIT OpenCourseWare http://ocw.mit.edu

6.042J / 18.062J Mathematics for Computer Science

Spring 2015 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.