Question

Find the mean of the following frequency distribution by direct method .
class 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50
frequency 7 8 15 9 10

Answer 1

Answer:

Mean = 7 + 8 + 15 + 9 + 10 / 5

Mean = 49 / 5

Mean = 9.8

Hope it helps to you!!

Answer 2

let us choose a = 25, h = 10 ,then,

$di = xi - 25 \: and \: ui = \frac{xi - 25}{10}$

using step deviation method the given in data as shown in picture:- (see the picture)

now,

The mean of data is given by :-