# R code to study the correlation
# between LotSize and WorkHrs for the Toluca data set


# Save the data file into a directory and 
# use the full path name:

toluca.data <- read.table(file = "z:/My Documents/teaching/stat_704/tolucadata.txt", 
header=FALSE, col.names = c('lotsize', 'workhrs'))

# attaching the data frame:

attach(toluca.data)


# finding the correlation coefficient between workhrs and lotsize:

cor(workhrs, lotsize)

# finding a 95% CI for rho using Fisher's z-transformation:

cor.test(workhrs, lotsize, method="pearson", conf.level=0.95)


# Example of nonparametric alternative:
# finding the Spearman rank correlation coefficient between workhrs and lotsize:

cor(workhrs, lotsize, method="spearman")