pub fn npk() -> Result<DataFrame, PolarsError>Expand description
§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.
§Usage:
npk
§Format:
The ‘npk’ data frame has 24 rows and 5 columns:
- ‘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).
§Source:
Imperial College, London, M.Sc. exercise sheet.
§References:
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
§Examples:
options(contrasts = c("contr.sum", "contr.poly"))
npk.aov <- aov(yield ~ block + N*P*K, npk)
npk.aov
summary(npk.aov)
coef(npk.aov)
options(contrasts = c("contr.treatment", "contr.poly"))
npk.aov1 <- aov(yield ~ block + N + K, data = npk)
summary.lm(npk.aov1)
se.contrast(npk.aov1, list(N=="0", N=="1"), data = npk)
model.tables(npk.aov1, type = "means", se = TRUE)