# To find out the concentration of SO_{2} in the air (in parts per million, i.e., ppm), the data was collected for 30 localities in a certain city and is presented below:

Find the mean concentration of SO_{2} in the air

**Solution:**

We will solve this question by the step-deviation method.

Mean, (x) = a + (Σf_{i}u_{i}/ Σf_{i}) × h

We know that, Class mark, x_{i} = (Upper class limit + Lower class limit)/2

Class size, h = 0.04

Taking assumed mean, a = 0.14

From the table, we obtain

Σf_{i} = 30

Σf_{i}u_{i} = - 31

Mean, (x) = a + (Σf_{i}u_{i}/ Σf_{i}) × h

= 0.14 + (- 31/30) × 0.04

= 0.14 - 0.041

= 0.099

The mean concentration of SO_{2} in the air is 0.099

**Video Solution:**

## To find out the concentration of SO_{2} in the air (in parts per million, i.e., ppm), the data was collected for 30 localities in a certain city and is presented in the table: Find the mean concentration of SO_{2} in the air

### NCERT Solutions for Class 10 Maths - Chapter 14 Exercise 14.1 Question 7:

To find out the concentration of SO_{2} in the air (in parts per million, i.e., ppm), the data was collected for 30 localities in a certain city and is presented in the table

Find the mean concentration of SO_{2} in the air

The mean concentration of SO2 in the air as per the data collected for 30 localities in a certain city is 0.099 ppm