# NCERT Class 11-Math's: Exemplar Chapter –15 Statistics Part 7

Get top class preparation for IMO Class-11 right from your home: fully solved questions with step-by-step explanation- practice your way to success.

Question 19:

The weights of coffee in jars is shown in the following table:

 Weight(in grams) Frequency 200-201 13 201-202 27 202-203 18 203-204 10 204-205 1 205-206 1

Determine variance and standard deviation of the above distribution.

Given: the weights of coffee in 70 jars

To find: the variance and standard deviation of the distribution

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

 Weight (in grams) Mid Value Frequency Total

Here mean,

So the above table with more columns is as shown below,

 Weight (in grams) Mid Value Frequency Total

And we know standard deviation is

Substituting values from above table, we get

And

Hence the variance and standard deviation of the distribution are 1.166g and 1.08 respectively.

Developed by: