

   DDaattaa ffrroomm aann OOaattss FFiieelldd TTrriiaall

   AArrgguummeennttss::

          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.

   FFoorrmmaatt::

        This data frame contains the following columns:

   DDeessccrriippttiioonn::

        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.

   SSoouurrccee::

        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.

   EExxaammpplleess::

        data(oats)
        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)
        # next line not implemented in R
        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)

