Intro to NHANES & Sampling Kaelen Medeiros Product Data - - PowerPoint PPT Presentation

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intro to nhanes sampling

Intro to NHANES & Sampling Kaelen Medeiros Product Data - - PowerPoint PPT Presentation

Aug 28, 2023 418 likes •605 views

DataCamp Experimental Design in R EXPERIMENTAL DESIGN IN R Intro to NHANES & Sampling Kaelen Medeiros Product Data Scientist at DataCamp DataCamp Experimental Design in R Intro to NHANES dataset NHANES = National Health and Nutrition

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DataCamp Experimental Design in R

Intro to NHANES & Sampling

EXPERIMENTAL DESIGN IN R

Kaelen Medeiros

Product Data Scientist at DataCamp

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DataCamp Experimental Design in R

Intro to NHANES dataset

NHANES = National Health and Nutrition Examination Survey Conducted by the National Center for Health Statistics (NCHS), a division of the Centers for Disease Control (CDC) Data collected a variety of ways, including interviews & a physical exam Questions cover medical, dental, socioeconomic, dietary, and general health- related conditions

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DataCamp Experimental Design in R

Intro to Sampling

Probability Sampling: probability is used to select the sample (in various ways) Non-probability Sampling: probability is not used to select the sample Voluntary response: whoever agrees to respond is the sample Convenience sampling: subjects convenient to the researcher are chosen.

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DataCamp Experimental Design in R

Sampling

Simple Random Sampling (SRS) Stratified Sampling Cluster Sampling Systematic Sampling Multi-stage Sampling

sample() dataset %>% group_by(strata_variable) %>% sample_n() cluster(dataset, cluster_var_name, number_to_select, method = "option")

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DataCamp Experimental Design in R

Let's practice!

EXPERIMENTAL DESIGN IN R

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DataCamp Experimental Design in R

Randomized Complete Block Designs

EXPERIMENTAL DESIGN IN R

Kaelen Medeiros

Product Data Scientist at DataCamp

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DataCamp Experimental Design in R

RCBDs

Randomized - the treatment is assigned randomly inside each block Complete - each treatment is used the same number of times in every block Block - experimental groups are blocked to be similar (e.g. by sex) Design - this is your experiment!

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DataCamp Experimental Design in R

RCBD Workflow

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DataCamp Experimental Design in R

agricolae

library(agricolae) trt <- letters[1:4] rep <- 4 design.rcbd <- design.rcbd(trt, r = rep, seed = 42, serie = 0) design.rcbd$sketch [,1] [,2] [,3] [,4] [1,] "d" "c" "a" "b" [2,] "b" "a" "d" "c" [3,] "d" "a" "b" "c" [4,] "a" "b" "d" "c"

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DataCamp Experimental Design in R

Let's practice!

EXPERIMENTAL DESIGN IN R

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DataCamp Experimental Design in R

Balanced Incomplete Block Designs (BIBD)

EXPERIMENTAL DESIGN IN R

Kaelen Medeiros

Product Data Scientist at DataCamp

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DataCamp Experimental Design in R

Balanced Incomplete Block Designs

Balanced - each pair of treatments occur together in a block an equal number of times Incomplete - not every treatment will appear in every block Block - experimental groups are blocked to be similar (e.g. by sex) Design - this is your experiment!

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DataCamp Experimental Design in R

Is there a BIBD?

Let: t = # of treatments k = # of treatments per block r = # replications λ = r × t − 1 (k − 1)

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DataCamp Experimental Design in R

BIBD examples (1)

λ = r × t − 1 (k − 1)

λ = 2 * (2-1) / 4-1 λ = 2/3 = 0.667

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DataCamp Experimental Design in R

Invalid BIBD

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DataCamp Experimental Design in R

BIBD examples (2)

λ = r × t − 1 (k − 1)

λ = 3 * (3-1) / 4-1 λ = 6/3 = 2

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DataCamp Experimental Design in R

Valid BIBD

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DataCamp Experimental Design in R

Let's practice!

EXPERIMENTAL DESIGN IN R