How do you find the frequency density in a histogram?

To find the frequency density in a histogram, divide the frequency by the class width for each interval.

In a histogram, the frequency density is used to represent the data in a way that accounts for varying class widths. This is important because it ensures that the area of each bar accurately reflects the frequency of the data within that interval. To calculate the frequency density, you need two pieces of information: the frequency (the number of data points within a class interval) and the class width (the range of values within that interval).

First, identify the frequency for each class interval. This is usually given in a frequency table or can be counted from the data set. Next, determine the class width for each interval. The class width is found by subtracting the lower boundary of the interval from the upper boundary. For example, if a class interval ranges from 10 to 20, the class width is 20 - 10 = 10.

Once you have both the frequency and the class width, you can calculate the frequency density by dividing the frequency by the class width. For instance, if the frequency is 30 and the class width is 10, the frequency density would be 30 ÷ 10 = 3. This means that the height of the bar in the histogram for that interval should be 3.

By using frequency density, histograms can accurately represent data even when class intervals are of different widths, making it easier to compare the distribution of data across different intervals.