potash {asbio}

Potash/cotton strength data

Description

An oft-cited RCBD example is an agricultural experiment which evaluates the effect of levels of of soil K_2O (potash) on the breaking strength of cotton fibers (Cochran and Cox 1957). Five levels of K_2O were used in the soil subplots ( 36, 54, 72, 108, and 144 lbs per acre) and a single sample of cotton was taken from each of five subplot. The experiment had three blocks, and each of the K_2O treatments was randomly assigned to the five subplots within each block.

Usage

data(potash)

Format

A data frame with 15 observations on the following 3 variables.

treatment

a factor with levels 36 54 72 108 144

block

a factor with levels 1 2 3

strength

a numeric vector

Source

Cochran, W. G. and G. M. Cox (1957) Experimental Designs (Second Edition). New York: John Wiley & Sons.