# Author: Adolfo J. Rumbos
# Date: 9/2/2008
#
# This code performs a randomization test on a subset of the Westvaco 
# data found on page 5 of Statistics in Action by Watkins, Sheaffer and 
# Cobb.
#
# The subset consists of the 10 hourly workers involved the second of
# the five rounds of layoffs.  Three of the 10 workers were laid off  
# in that round. 
#
# The 10 hourly workers involved in the 2nd round of layoffs are entered into
# a vector called hourly2
#

hourly2 <- c(25,38,56,48,55,64,55,55,33,35)

#
# This code draws random samples of size 3, without replacement, 
# from hourly2, and determines whether the average is >=58.
# The sampling is repeated NRep times. The proportion of the
# samples that have an average age or 58 or more, p_hat, is computed.
#
NRep <- 1000 	# NRep is the number of samples drawn

NYes <- 0		# NYes counts the number of samples that have mean 
			# of 58 or more

for (i in 1:NRep) # Sets up a loop from 1 to NRep

{			# Begins body of loop

NYes <- NYes + (mean(sample(hourly2,3,replace=F))>=58)

}			# End of loop

p_hat <- NYes/NRep # Computes observed proportion, p_hat, of samples with mean
			# larger than or equal to 58

p_hat 		# Prints p_hat