Counts of yellow/white and sweet/starchy maize kernels by 15 observers
pearl.kernels.Rd
Counts of yellow/white and sweet/starchy kernels on each of 4 maize ears by 15 observers.
Format
A data frame with 59 observations on the following 6 variables.
ear
ear, 8-11
obs
observer, 1-15
ys
number of yellow starchy kernels
yt
yellow sweet
ws
white starchy
wt
white sweet
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:
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 |
Source
Raymond Pearl, 1911. The Personal Equation In Breeding Experiments Involving Certain Characters of Maize, Biol. Bull., 21, 339-366. https://www.biolbull.org/cgi/reprint/21/6/339.pdf
Examples
if (FALSE) { # \dontrun{
library(agridat)
data(pearl.kernels)
dat <- pearl.kernels
libs(lattice)
xyplot(ys+yt+ws+wt~obs|ear, dat, type='l', as.table=TRUE,
auto.key=list(columns=4),
main="pearl.kernels", xlab="observer",ylab="kernels",
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), main="pearl.kernels",
ylab="P-value for test of 9:3:3:1 distribution")
} # }