Weight Gain in Rats

Source: R/AgainStart.R

The data come from an experiment to study the gain in weight of rats fed on four different diets, distinguished by amount of protein (low and high) and by source of protein (beef and cereal).

WEIGHTGAIN

Format

A data frame with 40 observations on the following 3 variables:

  • proteinsource (a factor with levels Beef and Cereal)

  • proteinamount (a factor with levels High and Low)

  • weightgain (weight gained in grams)

Source

Hand, D. J., F. Daly, A. D. Lunn, K. J. McConway, and E. Ostrowski. 1994. A Handbook of Small Datasets. Chapman and Hall/CRC, London.

Details

The design of the experiment is a completely randomized design with ten rats in each of the four treatments.

References

Ugarte, M. D., Militino, A. F., and Arnholt, A. T. 2015. Probability and Statistics with R, Second Edition. London: Chapman & Hall.

Examples

ggplot(data = WEIGHTGAIN, aes(x = proteinamount, y = weightgain, 
fill = proteinsource)) + geom_boxplot()

aov(weightgain ~ proteinsource*proteinamount, data = WEIGHTGAIN)
#> Call:
#>    aov(formula = weightgain ~ proteinsource * proteinamount, data = WEIGHTGAIN)
#> 
#> Terms:
#>                 proteinsource proteinamount proteinsource:proteinamount
#> Sum of Squares          220.9        1299.6                       883.6
#> Deg. of Freedom             1             1                           1
#>                 Residuals
#> Sum of Squares     8049.4
#> Deg. of Freedom        36
#> 
#> Residual standard error: 14.95307
#> Estimated effects may be unbalanced