Frequency Histogram

Frequency Histogram

How to make a frequency histogram from the given data and solve frequency histogram problems: examples and their solutions.

Example 1

The given table shows test scores. For the given table, make a frequency histogram.

Draw the histogram axes like this.

Set the vertical axis
as the Frequency:
from 0 to 8.

And set the horizontal axis
as the Test Scores:
from 50-59 to 90-99.

The frequency of 50-59 is 2.

So draw a vertical bar in the histogram
whose height is 2.

The frequency of 60-69 is 3.

So draw a vertical bar
whose height is 3.

Draw the bar right next to the previous bar
so that there would be no space between the bars.

The frequency of 70-79 is 7.

So draw a vertical bar
whose height is 7.

Draw the bar right next to the previous bar.

The frequency of 80-89 is 6.

So draw a vertical bar
whose height is 6.

Draw the bar right next to the previous bar.

The frequency of 90-99 is 2.

So draw a vertical bar
whose height is 2.

Draw the bar right next to the previous bar.

So this histogram is the answer.

Example 2

The given histogram shows test scores for students. For the given histogram, find the total number of students.

The heights of the bars
are the frequencies of the intervals.

So, to find the total number of students,
add the heights of the bars.

So the total number of students, n, is
3 + 6 + 7 + 4 + 1.

3 + 6 = 9
7 + 4 = 11

9 + 1 = 10

10 + 11 = 21

So 21 is the answer.