t.test.cluster {Hmisc} | R Documentation |
Does a 2-sample t-test for clustered data.
t.test.cluster(y, cluster, group, conf.int = 0.95) ## S3 method for class 't.test.cluster': print(x, digits, ...)
y |
normally distributed response variable to test |
cluster |
cluster identifiers, e.g. subject ID |
group |
grouping variable with two values |
conf.int |
confidence coefficient to use for confidence limits |
x |
an object created by t.test.cluster |
digits |
number of significant digits to print |
... |
unused |
a matrix of statistics of class t.test.cluster
Frank Harrell
Donner A, Birkett N, Buck C, Am J Epi 114:906-914, 1981.
Donner A, Klar N, J Clin Epi 49:435-439, 1996.
Hsieh FY, Stat in Med 8:1195-1201, 1988.
set.seed(1) y <- rnorm(800) group <- sample(1:2, 800, TRUE) cluster <- sample(1:40, 800, TRUE) table(cluster,group) t.test(y ~ group) # R only t.test.cluster(y, cluster, group) # Note: negate estimates of differences from t.test to # compare with t.test.cluster