Question

If the mean of the following distribution is 54, find the value of P.
Class : 0–20 20–40 40–60 60–80 80–100 ,
Frequency : 7 p 10 9 13 .

Answer 1

Mean:
The mean of a number of observation is the sum of the values of all the observations divided by the total number of observations.

Mean=sum of all the observations/total number of observations

Direct method:
In this method find the class marks of class interval. These class marks would serve as the representative of whole class and are represented by xi. For each class interval we have the frequency( fi) corresponding to the class mark (xi).

CLASS MARKS =( lower limit + upper limit)/2
Then find the product of fi, & xi for each class interval. Find Σfi & Σfixi.

Use the formula :
Mean = Σfixi/ Σfi

SOLUTION IS IN THE ATTACHMENT

HOPE THIS WILL HELP YOU....

Answer 2

Answer:

Step-by-step explanation:

Mean= sigma fixi/ sigma fi=2370+30p/ 39+p 54= 2370+30p/39+p( mean 54= given 54(39+p) = 2370+30p 2106+ 54p = 2370+30p 54p -30p = 2370-2106 24p= 264 p= 11 hence prooved