Question

please answer fast.........

Answer 1

Please follow the table to find out midpoint with the class interval and frequency, we can find midpoint by adding class intervals and dividing them with 2. 
then in order to find the mean, we will multiply frequency with midpoints individually.

The sum of Frequency = 100

and the sum of Frequency x midpoint = 11,400 

In order to find the mean, we will divide sum of frequency x midpoint with the sum of frequency. 

11400/100 = 114 is the mean.

In order to find the deviation, we will subtract midpoints with mean 

Deviation = midpoint - mean 

Answer 2

According to me to find mean deviation,we need to find out mean first.

Mean = Sum of x value /No.of value=
9+11+14+6+8+15+10+20+7÷ 9= 11.11 (Round figure)= 12

This, Deviation would be as under

9-12 =-3
11-12=-1
14-12=2
6-12=-6
8-12=-4
15-12=3
10-12=-2
20-12=8
7-12=-5

I hope it helps