The frequency measures the number of times an event occurs in a data set.
The frequency measures the number of times an event occurs in a data set. The absolute frequency counts how often each event occurred in the sample whereas the relative frequency divides the absolute frequencies by the total number of events. This gives the relative probabilities of the occurrence of a particular event.
Frequencies are often plotted by histograms or kernel density estimates. When plotting absolute and relative frequencies with the histogram the shape of the distribution does not change. Only the values on the x-axis change.