@subsubheading 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.

@subsubheading Format

@table @code
@item block
Which block (1 to 6).
@item N
Indicator (0/1) for the application of nitrogen.
@item P
Indicator (0/1) for the application of phosphate.
@item K
Indicator (0/1) for the application of potassium.
@item yield
Yield of peas, in pounds/plot. Plots were 1/70 acre.
@end table

@subsubheading Source

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

@subsubheading References

Venables, W. N. and Ripley, B. D. (2002). @cite{Modern Applied Statistics
with S}. Fourth edition. New York: Springer.

@subsubheading Examples

@example
@INCLUDE_DATASET_EXAMPLE_SCRIPT{npk_1.m}
@end example
