Question

Construct the simple frequency distribution from the following data:

Mid-value	5	15	25	35	45	55
Frequency	2	8	15	12	7	6

Answer 1

The class interval can be calculated from the mid-points using the following adjustment formula.

The value obtained is then added to the mid point to obtain the upper limit and subtracted from the mid-point to obtain the lower limit.

For the given data, the class interval is calculated by the following value of adjustment.

Thus, we add and subtract 5 to each mid-point to obtain the class interval.

For instance:

The lower limit of first class = 5 – 5 = 0

Upper limit of first class = 5 + 5 = 10

Thus, the first class interval is (0 − 10). Similarly, we can calculate the remaining class intervals.

Mid-value	Class-interval	Frequency (f)
5 15 25 35 45 55	0 − 10 10 − 20 20 − 30 30 − 40 40 − 50 50 − 60	2 8 15 12 7 6
		∑f = 50