patch: The Patch Data

In bootstrap: Functions for the Book "An Introduction to the Bootstrap"

Description

Eight subjects wore medical patches designed to infuse a naturally-occuring hormone into the blood stream.

Usage

data(patch)

Format

A data frame with 8 observations on the following 6 variables.

subject

a numeric vector

placebo

a numeric vector

oldpatch

a numeric vector

newpatch

a numeric vector

z

a numeric vector, oldpatch - placebo

y

a numeric vector, newpatch - oldpatch

Details

Eight subjects wore medical patches designed to infuse a certain naturally-occuring hormone into the blood stream. Each subject had his blood levels of the hormone measured after wearing three different patches: a placebo patch, an "old" patch manufactured at an older plant, and a "new" patch manufactured at a newly opened plant.

The purpose of the study was to show bioequivalence. Patchs from the old plant was already approved for sale by the FDA (food and drug administration). Patches from the new facility would not need a full new approval, if they could be shown bioequivalent to the patches from the old plant.

Bioequivalence was defined as

|E(new)-E(old)|/(E(old)-E(placebo)) <= 0.20

The book uses this to investigate bias of ratio estimation.

Source

Efron, B. and Tibshirani, R. (1993) An Introduction to the Bootstrap. Chapman and Hall, New York, London.

Examples

str(patch) 
 theta <- function(ind){
      Y <- patch[ind,"y"]
      Z <- patch[ind,"z"]
      mean(Y)/mean(Z) }
patch.boot <- bootstrap(1:8, 2000, theta)
names(patch.boot)          
hist(patch.boot$thetastar)
abline(v=c(-0.2, 0.2), col="red2")
theta(1:8) #sample plug-in estimator
abline(v=theta(1:8) , col="blue")
# The bootstrap bias estimate:
mean(patch.boot$thetastar) - theta(1:8)
sd(patch.boot$thetastar) # bootstrapped standard error

Example output

'data.frame':	8 obs. of  6 variables:
 $ subject : int  1 2 3 4 5 6 7 8
 $ placebo : num  9243 9671 11792 13357 9055 ...
 $ oldpatch: num  17649 12013 19979 21816 13850 ...
 $ newpatch: num  16449 14614 17274 23798 12560 ...
 $ z       : num  8406 2342 8187 8459 4795 ...
 $ y       : num  -1200 2601 -2705 1982 -1290 ...
[1] "thetastar"      "func.thetastar" "jack.boot.val"  "jack.boot.se"  
[5] "call"          
[1] -0.0713061
[1] 0.004833768
[1] 0.09577782

bootstrap documentation built on June 17, 2019, 5:04 p.m.