Question

The electricity bills (in rupees) of 40 houses in a locality are given below:
116,127,107,100,80,82,91,101,65,95,87,81,105,129,92,75,89,78,87,81,59,52,65,101,115,108,95,65,98,62,84,76,63,128,121,61,118,108,116,130.
Construct a grouped frequency table.

Answer 1

The minimum observation is 800 and the maximum observation is 900.
So, range = 900 − 800 = 100
Class size = 10
Now, 100 $÷$10=10
i.e., we should have 10 classes each of size 10.
Therefore, classes of the same size covering the above data are 800-810, 810-820, 820-830, 830-840, 840-850, 850-860, 860-870, 870-880, 880-890 and 890-900.

Frequency distribution table:

Class	Tally mark	Frequency
800-810		3
810-820		2
820-830		1
830-840		8
840-850		5
850-860		1
860-870		3
870-880		1
880-890		1
890-900		5