agridat (version 1.12)

patterson.switchback: A switchback trial in dairy cattle

Description

A switchback trial in dairy cattle

Usage

data(patterson.switchback)

Format

A data frame with 36 observations on the following 4 variables.

y

response, milk FCM

trt

treatment factor, 4 levels

period

period factor, 3 levls

cow

cow factor, 12 levels

Details

None.

References

Lowry, S.R. 1989. Statistical design and analysis of dairy nutrition experiments to improve detection of milk response differences. Proceedings of the Conference on applied statistics in agriculture, 1989.

Examples

# NOT RUN {
data(patterson.switchback)
dat <- patterson.switchback

# Create a numeric period variable
dat$p <- as.numeric(substring(dat$period,2))

# Need to use 'terms' to preserve the order of the model terms
m1 <- aov(terms(y ~ cow + p:cow + period + trt, keep.order=TRUE), data=dat)
anova(m1) # Match table 2 of Lowry
## Analysis of Variance Table
##           Df Sum Sq Mean Sq F value    Pr(>F)
## cow       11 3466.0 315.091 57.1773 2.258e-06 ***
## cow:p     12  953.5  79.455 14.4182 0.0004017 ***
## period     1   19.7  19.740  3.5821 0.0950382 .
## trt        3   58.3  19.418  3.5237 0.0685092 .
## Residuals  8   44.1   5.511

# }