represent the following by a histogram?

wages 10-15 15-20 20-25 25-30 30-40 40-60 60-80

no of workers 7 19 27 15 12 12 8

Since, the class intervals are not equal, we need to make adjustments in the frequencies, otherwise the histogram would be a misleading diagram.

Method of adjustment:

1) Take the class which has the lowest class interval.

2) Do not adjust the frequencies of the lowest class.

3) Frequencies of other classes are then adjusted according with this lowest class interval.

4) Adjusted frequencies will decide the heights of each rectangle of the histogram. However, the widths will be according to the original class interval.

5) Frequencies of the class for which the difference between the lower and the upper limit is the same as that of the lowest class interval, will remain the same.

Below is the table showing the adjustments:
 

WagesNo. of workers (Frequency)AdjustedFrequency (f)
10 - 157-7
15 -2019-19
20 – 2527-27
25 - 3015-15
30 - 4012

Difference = 10

6
40 - 6012

Difference = 20

3
60 – 808

Difference = 20


 

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