#
### PROPORTIONS TEST FOR k INDEPENDENT SAMPLES
###
### DESCRIPTION:
###    Tests whether underlying proportions for k samples are equal.
###
### REQUIRED ARGUMENTS:
###    x = vector of k elements containing the number of successes for each sample.
### 	n = vector of k elements containing the total number of trials for each sample.
###    NOTE:  the elements in the x vector must correspond to the elements
###           in the n vector.
###
### REFERENCES:
###   Fienberg, S. E. (1983). The Analysis of Cross-Classified Categorical Data, 2nd ed.
###     The MIT Press, Cambridge, Mass.
###
###   Fleiss, J. L. (1981). Statistical Methods for Rates and Proportions, 2nd ed. 
###     Wiley, New York.
###
###   Snedecor, G. W. and Cochran, W. G. (1980). Statistical Methods, 7th ed. 
###     Iowa State University Press, Ames, Iowa.
#
x <- c(83,90,129,70)

n <- c(86,93,136,82)

conf.level <- .95

prop.test(x,n,conf.level=conf.level)