SASmixed (version 1.0-4)

BIB: Data from a balanced incomplete block design

Description

The BIB data frame has 24 rows and 5 columns.

Format

This data frame contains the following columns:

Block

an ordered factor with levels 1 < 2 < 3 < 8 < 5 < 4 < 6 < 7

Treatment

a treatment factor with levels 1 to 4.

y

a numeric vector representing the response

x

a numeric vector representing the covariate

Grp

a factor with levels 13 and 24

Source

Littel, R. C., Milliken, G. A., Stroup, W. W., and Wolfinger, R. D. (1996), SAS System for Mixed Models, SAS Institute (Data Set 5.4).

Details

These appear to be constructed data.

Examples

str(BIB)
if (require("lattice", quietly = TRUE, character = TRUE)) {
  xyplot(y ~ x | Block, BIB, groups = Treatment, type = c("g", "p"),
         aspect = "xy", auto.key = list(points = TRUE, space = "right",
         lines = FALSE))
}
if (require("lme4", quietly = TRUE, character = TRUE)) {
  options(contrasts = c(unordered = "contr.SAS", ordered = "contr.poly"))
  ## compare with Output 5.7, p. 188
  print(fm1BIB <- lmer(y ~ Treatment * x + (1 | Block), BIB))
  print(anova(fm1BIB))     # strong evidence of different slopes
  ## compare with Output 5.9, p. 193
  print(fm2BIB <- lmer(y ~ Treatment + x : Grp + (1 | Block), BIB))
  print(anova(fm2BIB))
}