Question

5) If the mean of the following data is 20.2, find the value of p. Variable (x) 10 15 20 25 30 Frequency (fi) 6 8 p 10 6​

Answer 1

p = 20

Explanation:

Step1 :

Multiply each value by its frequency then add up :

(10 × 16) + (15 × 8) + (20 × p) + (25 × 10) + (30 × 6) = 20p + 610

Step2 :

Calculate the total of the frequencies :

6 + 8 + p + 10 + 6 = p + 30

The mean is equal to

`(20p+610)/(p+30)`

Therefore

`20.2 = (20p+610)/(p+30)`

then

20.2 × (p + 30) = 20p + 610

then

20.2p + 606 = 20p + 610

Then

20.2p - 20p = 610 - 606

Then

0.2p = 4

Then

p = 4/(0.2)

= 20