Rate of Germination of Treated Guayule Seeds

SUMMARY:

The guayule data frame, a design object, has 96 rows and 5 columns. The guayule is a Mexican plant from which rubber is manufactured. Batches of 100 seeds of eight varieties ( variety ) of guayule were given one of four treatments ( treatment ), and planted; the number of plants that came up in each batch ( plants ) was recorded. In order to separate the effect of which flat (planting tray) a batch was planted on from the effect of the treatment, each flat was planted with seeds from only one variety, but all the treatments were represented in each flat. This data frame contains the following columns:

ARGUMENTS:

variety
factor with levels V1 through V8 labeling the variety of guayule.
treatment
factor with levels T1 through T4 labeling the treatment given to the seeds.
reps
1, 2, or 3. All eight varieties of plant are represented once in each rep .
plants
numeric vector givng the number seeds out of a batch of 100 that germinated.
flats
factor labeling in which of 24 flats (3 of each variety) a batch was planted.

SOURCE:

Federer, W.T. (1955) Experimental Design Theory and Applications. The Macmillan Company, New York.

John M. Chambers and Trevor J. Hastie, (eds.) Statistical Models in S, Wadsworth and Brooks, Pacific Grove, CA 1992, pg. 157.

EXAMPLES:

gaov <- aov(plants ~ variety * treatment + Error(flats))