Question

Observe the frequency polygon given alongside. Prepare frequency table and find mean of the net asset value.

Answer 1

1. Determining the class intervals

The x-coordinates of the points plotted on the frequency polygon represent the class marks (x_i).

The difference between two consecutive class marks is:

Class width (g) = 10.5 – 8.5 = 2

Using the class width, the lower and upper limits of each class interval are calculated as:

Lower limit = `x_i - g/2`

= x_i – 1

Upper limit = `x_i + g/2`

= x_i + 1

2. Frequency table

Class (Net Asset Value)	Class Mark (xi)	Frequency (No. of funds, fi)	Product (fi × xi)
7.5 – 9.5	8.5	20	170
9.5 – 11.5	10.5	40	420
11.5 – 13.5	12.5	30	375
13.5 – 15.5	14.5	25	362.5
15.5 – 17.5	16.5	15	247.5
Total		Σfi = 130	Σfixi = 1575

3. Calculating the mean

Using the direct method formula for grouped data:

Mean `(barx) = (sumf_ix_i)/(sumf_i)`

`(barx) = 1575/130 ≈ 12.1154`

Thus, the mean of the net asset value is approximately 12.12.