gomez.heteroskedastic {agridat} | R Documentation

## RCB in rice with heteroskedastic varieties

### Description

RCB in rice with heteroskedastic varieties, 35 genotypes, 3 reps

### Usage

    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

    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

    if(require(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)
    ## 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

[Package agridat version 1.16 Index]