Question

A) Find the arithmetic mean by step deviation method for the
given data.
Class Interval
10-20
20-30 30-40
40-50
50-60
60-70
Frequency
7
12
8.
7
11
5​

Answer 1

Answer:

so the answer is given there it is 38.6

Answer 2

for this method first we should find

xi

di

ui

and fiui

to find xi we should add class interval and divide by 2 for eg : 10-20 , 10+ 20/2 , 30/2, = 15

and then to find di we should subtract xi - a

a is the mid number in xi

to find ui we should divide xi- a by h

h is the difference of between class interval eg : 10 - 20 and the difference is 10

fiui is finded by multiply by both fi and ui