pearl.kernels {agridat} | R Documentation

## 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.

### 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. http://www.biolbull.org/cgi/reprint/21/6/339.pdf

### Examples

    data(pearl.kernels)
    dat <- pearl.kernels

    require(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")

[Package agridat version 1.16 Index]