npk {MASS}R Documentation

Classical N, P, K Factorial Experiment

Description

A classical N, P, K (nitrogen, phosphate, potassium) factorial experiment on the growth of peas conducted on 6 blocks. Each half of a fractional factorial design confounding the NPK interaction was used on 3 of the plots.

Arguments

block which block (label 1 to 6).
N indicator (0/1) for the application of nitrogen.
P indicator (0/1) for the application of phosphate.
K indicator (0/1) for the application of potassium.
yield Yield of peas, in pounds/plot (the plots were (1/70) acre).

Format

The npk data frame has 24 rows and 5 columns:

Source

Imperial College, London, M.Sc. exercise sheet.

Examples

data(npk)
npk.aov <- aov(yield ~ block + N*P*K, npk)
npk.aov
summary(npk.aov)
alias(npk.aov)
coef(npk.aov)
options(contrasts=c("contr.treatment", "contr.poly"))
npk.aov1 <- aov(yield ~ block + N + K, npk)
summary.lm(npk.aov1)
se.contrast(npk.aov1, list(N=="0", N=="1"), data=npk)
model.tables(npk.aov1, type="means", se=TRUE)

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