RCB experiment of rice, heteroskedastic varieties

data("gomez.heteroskedastic")

Format

A data frame with 105 observations on the following 4 variables.

gen: genotype
group: group of genotypes
rep: replicate
yield: yield

Details

RCB design with three reps. Genotypes 1-15 are hybrids, 16-32 are parents, 33-35 are checks.

Source

Gomez, K.A. and Gomez, A.A.. 1984, Statistical Procedures for Agricultural Research. Wiley-Interscience. Page 310.

Used with permission of Kwanchai Gomez.

References

None.

Examples


library(agridat)
data(gomez.heteroskedastic)
dat <- gomez.heteroskedastic

# Fix the outlier as reported by Gomez p. 311
dat[dat$gen=="G17" & dat$rep=="R2","yield"] <- 7.58

libs(lattice)
bwplot(gen ~ yield, dat, group=as.numeric(dat$group),
       ylab="genotype", main="gomez.heterogeneous")

# Match Gomez table 7.28
m1 <- lm(yield ~ rep + gen, data=dat)
anova(m1)
#> Analysis of Variance Table
#> 
#> Response: yield
#>           Df Sum Sq Mean Sq F value    Pr(>F)    
#> rep        2  3.306 1.65304  5.6164  0.005528 ** 
#> gen       34 40.020 1.17705  3.9992 5.806e-07 ***
#> Residuals 68 20.014 0.29432                      
#> ---
#> Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Response: yield
##           Df Sum Sq Mean Sq F value    Pr(>F)    
## rep        2  3.306 1.65304  5.6164  0.005528 ** 
## gen       34 40.020 1.17705  3.9992 5.806e-07 ***
## Residuals 68 20.014 0.29432