recovery {multcomp}

Recovery Time Data Set

Description

Recovery time after surgery.

Usage

data("recovery")

Format

This data frame contains the following variables

blanket

blanket type, a factor at four levels: b0, b1, b2, and b3.

minutes

response variable: recovery time after a surgical procedure.

Details

A company developed specialized heating blankets designed to help the body heat following a surgical procedure. Four types of blankets were tried on surgical patients with the aim of comparing the recovery time of patients. One of the blanket was a standard blanket that had been in use already in various hospitals.

Source

P. H. Westfall, R. D. Tobias, D. Rom, R. D. Wolfinger, Y. Hochberg (1999). Multiple Comparisons and Multiple Tests Using the SAS System. Cary, NC: SAS Institute Inc., page 66.

Examples

  ### set up one-way ANOVA
  amod <- aov(minutes ~ blanket, data = recovery)

  ### set up multiple comparisons: one-sided Dunnett contrasts
  rht <- glht(amod, linfct = mcp(blanket = "Dunnett"), 
              alternative = "less")

  ### cf. Westfall et al. (1999, p. 80)
  confint(rht, level = 0.9)

  ### the same
  rht <- glht(amod, linfct = mcp(blanket = c("b1 - b0 >= 0", 
                                             "b2 - b0 >= 0", 
                                             "b3 - b0 >= 0")))
  confint(rht, level = 0.9)