Frequency density of a class is the ratio of:

For example, if a class has a frequency of 10 and a class interval of 5, the frequency density is 2.

(a) The class frequency to the total frequency is the proportion of observations in a class to the total number of observations.

(c) The class interval to the class frequency is the width of a class interval divided by the number of observations in that class.

(d) None of these is the correct answer.