Question

The frequency distribution:

where A is a positive integer, has a variance of 160. Determine the value of A.

Answer 1

Given: frequency distribution table, where variance =160

To find: the value of A, where A is a positive number

Let us make a table of the given data and append other columns after calculations

And we know variance is

Substituting values from above table and also given variance=160, we get

⇒ A²=49

⇒ A=7

Hence the value of A is 7.