Question

Prepare a continuous grouped frequency distribution from the following data:

Mid-point	Frequency
5	4
15	8
25	13
35	12
45	6

Also find the size of class intervals.

Answer 1

The common difference of mid-point = 15 – 5 = 10

Let lower limit is a. So, upper limit will be = a + 10

As we know that:

Mid-value = `("Lower limit" + "Upper limit")/2`

`5 = (a + a + 10)/2`

2a + 10 = 10

2a = 10 – 10

a = 0

Therefore, the first interval is 0 – 10.

Now, a frequency distribution table for the given data is given below:

Mid-point	Class interval	Frequency
5	0 – 10	4
15	10 – 20	8
25	20 – 30	13
35	30 – 40	12
45	40 – 50	6