gomez.nonnormal2.Rd
RCB experiment of rice, measuring white heads
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.
library(agridat) data(gomez.nonnormal2) dat <- gomez.nonnormal2 # Gomez suggested sqrt transform dat <- transform(dat, twhite = sqrt(white+.5)) # QQ plots for raw/transformed data libs(reshape2, lattice) qqmath( ~ value|variable, data=melt(dat), main="gomez.nonnormal2 - raw/transformed QQ plot", scales=list(relation="free"))#>#> Analysis of Variance Table #> #> Response: twhite #> 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 #> --- #> Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1## 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