oats {MASS} | R Documentation

## Data from an Oats Field Trial

### Description

The yield of oats from a split-plot field trial using three varieties and four levels of manurial treatment. The experiment was laid out in 6 blocks of 3 main plots, each split into 4 sub-plots. The varieties were applied to the main plots and the manurial treatments to the sub-plots.

### Usage

    data(oats)

### Format

This data frame contains the following columns:

`B`
  Blocks, levels I, II, III, IV, V and VI
`V`
  Varieties, 3 levels.
`N`
  Nitrogen (manurial) treatment, levels 0.0cwt, 0.2cwt, 0.4cwt and 0.6cwt, showing the application in cwt/acre.
`Y`
  Yields in 1/4lbs per sub-plot, each of area 1/80 acre.

### Source

Yates, F. (1935) Complex experiments, Journal of the Royal Statistical Society Suppl. 2, 181–247.

Also given in Yates, F. (1970) Experimental design: Selected papers of Frank Yates, C.B.E, F.R.S. London: Griffin.

### References

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

### Examples

    oats$Nf <- ordered(oats$N, levels = sort(levels(oats$N)))
    oats.aov <- aov(Y ~ Nf*V + Error(B/V), data = oats, qr = TRUE)
    summary(oats.aov)
    summary(oats.aov, split = list(Nf=list(L=1, Dev=2:3)))
    par(mfrow = c(1,2), pty = "s")
    plot(fitted(oats.aov[[4]]), studres(oats.aov[[4]]))
    abline(h = 0, lty = 2)
    oats.pr <- proj(oats.aov)
    qqnorm(oats.pr[[4]][,"Residuals"], ylab = "Stratum 4 residuals")
    qqline(oats.pr[[4]][,"Residuals"])

    par(mfrow = c(1,1), pty = "m")
    oats.aov2 <- aov(Y ~ N + V + Error(B/V), data = oats, qr = TRUE)
    model.tables(oats.aov2, type = "means", se = TRUE)

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