agridat (version 1.5)

pearl.kernels: Counts of yellow/white and sweet/starchy maize kernels by 15 observers

Description

Counts of yellow/white and sweet/starchy kernels on each of 4 maize ears by 15 observers.

Usage

data(pearl.kernels)

source

Raymond Pearl, 1911. The Personal Equation In Breeding Experiments Involving Certain Characters of Maize, Biol. Bull., 21, 339-366. www.biolbull.org/cgi/reprint/21/6/339.pdf

Details

An ear of white sweet corn was crossed with an ear of yellow starchy corn. The F1 kernels of the cross were grown and a sample of four ears was harvested. The F2 kernels of these ears were classified by each of 15 observers into white/yellow and sweet/starchy. By Mendelian genetics, the kernels should occur in the ratio 9 yellow starch, 3 white starch, 3 yellow sweet, 1 white sweet. The observers had the following positions: ll{ 1 Plant pathologist 2 Asst plant pathologist 3 Prof agronomy 4 Asst prof agronomy 5 Prof philosophy 6 Biologist 7 Biologist 8 Asst biologist 9 Computer 10 Farmer 11 Prof plant physiology 12 Instructor plant physiology 13 Asst plant physiology 14 Asst plant physiology 15 Prof biology }

Examples

dat <- pearl.kernels

xyplot(ys+yt+ws+wt~obs|ear, dat, type='l', as.table=TRUE, auto.key=TRUE,
layout=c(4,1), scales=list(x=list(rot=90)))

# Test hypothesis that distribution is 'Mendelian' 9:3:3:1
dat$pval <- apply(dat[, 3:6], 1, function(x)
                  chisq.test(x, p=c(9,3,3,1)/16)$p.val)
dotplot(pval~obs|ear, dat, layout=c(1,4))