chisq.test
{stats}
Chi-Squared test (e.g. for cross-tabulations)
as.factor
{base}
Coerce a vector to factor
cor.test
{stats}
Test for Association/Correlation Between Paired Samples
as.numeric
{base}
Coerce a vector to numeric
tapply
{base}
Create statistical summaries by group based on the levels of one or several factors
par
{graphics}
Set parameters of the plotting device
which
{base}
return indexes of TRUE entries of a logical vector
barplot
{graphics}
Plot a simple bar plot
prop.table
{base}
Transform frequency table into table of proportions
cor
{stats}
Calculate Correlation Matrix
addmargins
{stats}
Puts Arbitrary Margins on Multidimensional Tables or Arrays
The end!