case0301 {Sleuth2}

Cloud Seeding

Description

Does dropping silver iodide onto clouds increase the amount of rainfall they produce? In a randomized experiment, researchers measured the volume of rainfall in a target area (in acre-feet) on 26 suitable days in which the clouds were seeded and on 26 suitble days in which the clouds were not seeded.

Usage

case0301

Format

A data frame with 52 observations on the following 2 variables.

Rainfall

the volume of rainfall in the target area (in acre-feet)

Treatment

a factor with levels "Unseeded" and "Seeded" indicating whether the clouds were unseeded or seeded.

Source

Ramsey, F.L. and Schafer, D.W. (2002). The Statistical Sleuth: A Course in Methods of Data Analysis (2nd ed), Duxbury.

References

Simpson, J., Olsen, A., and Eden, J. (1975). A Bayesian Analysis of a Multiplicative Treatment Effect in Weather Modification. Technometrics 17: 161–166.

Examples

str(case0301)
boxplot(Rainfall ~ Treatment, case0301)
boxplot(log(Rainfall) ~ Treatment, case0301)
library(lattice)
bwplot(Treatment ~ log(Rainfall), case0301)
bwplot(log(Rainfall) ~ Treatment, case0301)