gomez.stripplot {agridat} | R Documentation

## Rice strip-plot experiment

### Description

A strip-plot experiment with three reps, variety as the horizontal strip and nitrogen fertilizer as the vertical strip.

### Format

`yield`

  Grain yield in kg/ha

`rep`

  Rep

`nitro`

  Nitrogen fertilizer in kg/ha

`gen`

  Rice variety

`col`

  column

`row`

  row

### Details

Note, this is a subset of the the 'gomez.stripsplitplot' data.

### Source

Gomez, K.A. and Gomez, A.A.. 1984, Statistical Procedures for Agricultural Research. Wiley-Interscience. Page 110.

Used with permission of Kwanchai Gomez.

### References

Jan Gertheiss (2014). ANOVA for Factors With Ordered Levels. J Agric Biological Environmental Stat, 19, 258-277.

### Examples

    data(gomez.stripplot)
    dat <- gomez.stripplot

    # Gomez figure 3.7
    if(require(desplot)){
      desplot(gen ~ col*row, data=dat,
              # aspect unknown
              out1=rep, out2=nitro, num=nitro, cex=1,
              main="gomez.stripplot")
    }

    # Gertheiss figure 1
    # library(lattice)
    # dotplot(factor(nitro) ~ yield|gen, data=dat)

    # Gomez table 3.12
    tapply(dat$yield, dat$rep, sum)
    tapply(dat$yield, dat$gen, sum)
    tapply(dat$yield, dat$nitro, sum)

    # Gomez table 3.15.  Anova table for strip-plot
    dat <- transform(dat, nf=factor(nitro))
    m1 <- aov(yield ~ gen * nf + Error(rep + rep:gen + rep:nf), data=dat)
    summary(m1)
    ## Error: rep
    ##           Df  Sum Sq Mean Sq F value Pr(>F)
    ## Residuals  2 9220962 4610481

    ## Error: rep:gen
    ##           Df   Sum Sq  Mean Sq F value  Pr(>F)
    ## gen        5 57100201 11420040   7.653 0.00337 **
    ## Residuals 10 14922619  1492262
    ## ---
    ## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

    ## Error: rep:nf
    ##           Df   Sum Sq  Mean Sq F value  Pr(>F)
    ## nf         2 50676061 25338031   34.07 0.00307 **
    ## Residuals  4  2974908   743727
    ## ---
    ## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

    ## Error: Within
    ##           Df   Sum Sq Mean Sq F value   Pr(>F)
    ## gen:nf    10 23877979 2387798   5.801 0.000427 ***
    ## Residuals 20  8232917  411646

    # More compact view
    ## library(agricolae)
    ## with(dat, strip.plot(rep, nf, gen, yield))

    ## Analysis of Variance Table
    ## Response: yield
    ##        Df   Sum Sq  Mean Sq F value    Pr(>F)
    ## rep     2  9220962  4610481 11.2001 0.0005453 ***
    ## nf      2 50676061 25338031 34.0690 0.0030746 **
    ## Ea      4  2974908   743727  1.8067 0.1671590
    ## gen     5 57100201 11420040  7.6528 0.0033722 **
    ## Eb     10 14922619  1492262  3.6251 0.0068604 **
    ## gen:nf 10 23877979  2387798  5.8006 0.0004271 ***
    ## Ec     20  8232917   411646

    # Mixed-model version
    ## library(lme4)
    ## m3 <- lmer(yield ~ gen * nf + (1|rep) + (1|rep:nf) + (1|rep:gen), data=dat)
    ## anova(m3)

    ## Analysis of Variance Table
    ##        Df   Sum Sq  Mean Sq F value
    ## gen     5 15751300  3150260  7.6528
    ## nf      2 28048730 14024365 34.0690
    ## gen:nf 10 23877979  2387798  5.8006

[Package agridat version 1.16 Index]