RVAideMemoire (version 0.9-45-2)

cochran.qtest: Cochran's Q test

Description

Performs the Cochran's Q test for unreplicated randomized block design experiments with a binary response variable and paired data. If the p-value of the test is significant, the function performs pairwise comparisons by using the Wilcoxon sign test.

Usage

cochran.qtest(formula, data, alpha = 0.05, p.method = "fdr")

Arguments

formula

a formula of the form a ~ b | c, where a, b and c give the data values and corresponding groups and blocks, respectively. a can be a numeric vector or a factor, with only two possible values

data

an optional data frame containing the variables in the formula formula. By default the variables are taken from environment(formula).

alpha

significance level to compute pairwise comparisons.

p.method

method for p-values correction. See help of p.adjust.

Value

• method.test
  a character string giving the name of the global test computed.
• data.name
  a character string giving the name(s) of the data.
• alternative
  a character string describing the alternative hypothesis.
• estimate
  the estimated probabilities.
• null.value
  the value of the difference in probabilities under the null hypothesis, always 0.
• statistic
  test statistics (Pearson's Chi-squared test only).
• parameter
  test degrees of freedom (Pearson's Chi-squared test only).
• p.value
  p-value of the global test.
• alpha
  significance level.
• p.adjust.method
  method for p-values correction.
• p.value.multcomp
  data frame of pairwise comparisons result.
• method.multcomp
  a character string giving the name of the test computed for pairwise comparisons.

Details

If the response is a 0/1 variable, the probability of the '1' group is tested. In any other cases, the response is transformed into a factor and the probability of the second level is tested.

Examples

response <- c(0,1,1,0,0,1,0,1,1,1,1,1,0,0,1,1,0,1,0,1,1,0,0,1,0,1,1,0,0,1)
fact <- gl(3,1,30,labels=LETTERS[1:3])
block <- gl(10,3,labels=letters[1:10])
cochran.qtest(response~fact|block)