Chi-square tests are useful for categorical data. They can be used to test whether a vector of probabilities associated with each of several possible outcomes is equal to some null value. That null…
Although plot() can produce bar charts, the barplot() function is often more convenient. In this video we introduce this function and illustrate its use to produce bar charts that display one and…
The plot() function is the ultimate generic function in R. It is highly flexible, and produces a variety of different plot types depending upon the class of the objects that it operates on and the…
Frequency distributions (univariate and joint) can be displayed in contingency tables, or cross-tabulations. In this video we show how tapply() can be used to create such tables, but we…