Description Usage Format Details Source References Examples

RCB trial of rice measuring white heads

1 | ```
data("gomez.nonnormal2")
``` |

A data frame with 42 observations on the following 3 variables.

`gen`

genotype

`rep`

replicate

`white`

percentage of white heads

The data are the percent of white heads from a rice variety trial of 14 varieties with 3 reps. Because many of the values are less than 10, the suggested data transformation is sqrt(x+.5).

Gomez, K.A. and Gomez, A.A.. 1984,
*Statistical Procedures for Agricultural Research*.
Wiley-Interscience. Page 300.

Used with permission of Kwanchai Gomez.

None.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | ```
data(gomez.nonnormal2)
dat <- gomez.nonnormal2
# Gomez suggested sqrt transform
dat <- transform(dat, twhite = sqrt(white+.5))
# QQ plots for raw/transformed data
if(require(reshape2) & require(lattice))
qqmath( ~ value|variable, data=melt(dat),
main="gomez.nonnormal2 - raw/transformed QQ plot",
scales=list(relation="free"))
# Gomez anova table 7.21
m1 <- lm(twhite ~ rep + gen, data=dat)
anova(m1)
## Response: twhite2
## Df Sum Sq Mean Sq F value Pr(>F)
## rep 2 2.401 1.2004 1.9137 0.1678
## gen 13 48.011 3.6931 5.8877 6.366e-05 ***
## Residuals 26 16.309 0.6273
``` |

agridat documentation built on May 2, 2019, 4:01 p.m.

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