Understanding the Mean Graphically: Two bars

In this lesson we understand the mean of a dataset using graphical method.

Suppose we are given a bar graph showing two bars of data. Here we are required to find the mean of given data graphically.

Rules to find the mean graphically

In the bar graph we find the heights of the two bars.

The average or mean of these heights is found.

We then draw a third bar with the average height found in second step.

The height of this third bar gives the mean or average of given data set graphically.

The two bars in a bar graph have heights 16 and 22. What height a new bar should have so that it has the mean height of the two bars?

Solution

Step 1:

Heights of given bars 16, 22

Step 2:

Mean height = $frac{(16 + 22)}{2} = frac{38}{2}$ = 19

So height of new bar = 19

The two bars in a bar graph have heights 15 and 27. What height a new bar should have so that it has the mean height of the two bars?

Solution

Step 1:

Heights of given bars 15, 27

Step 2:

Mean height = $frac{(15 + 27)}{2} = frac{42}{2}$ = 21

So height of new bar = 21