| % File src/library/datasets/man/npk.Rd |
| % Part of the R package, https://www.R-project.org |
| % copyright (C) 1999 W. N. Venables and B. D. Ripley |
| % Distributed under GPL 2 or later |
| |
| \name{npk} |
| \alias{npk} |
| \title{ |
| 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 \code{npk} data frame has 24 rows and 5 columns: |
| \describe{ |
| \item{\code{block}}{ |
| which block (label 1 to 6). |
| } |
| \item{\code{N}}{ |
| indicator (0/1) for the application of nitrogen. |
| } |
| \item{\code{P}}{ |
| indicator (0/1) for the application of phosphate. |
| } |
| \item{\code{K}}{ |
| indicator (0/1) for the application of potassium. |
| } |
| \item{\code{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) |
| \emph{Modern Applied Statistics with S.} Fourth edition. Springer. |
| } |
| % This gets different roundings |
| \examples{\donttest{ |
| 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) |
| }} |
| \keyword{datasets} |