Question

A study was conducted to find out the concentration of sulphur dioxide in the air in parts per million (ppm) of a certain city. The data obtained for 30 days is as follows

NCERT Solutions for Class 9 Maths Chapter 15 Probability Ex 15.1 Q12

You were asked to prepare a frequency distribution table, regarding the concentration of sulphur dioxide in the air in parts per million of a certain city for 30 days. Using this table, find the probability of the concentration of sulphur dioxide in the interval 0.12-0.16 on any of these days.

Answer 1

Answer:

Step-by-step explanation:

Concentration of

sulphur dioxide (in ppm) Frequency  

0.00 - 0.04  4

0.04 - 0.08  9

0.08 - 0.12  9

0.12 - 0.16 2  

0.16 - 0.20  4

0.20 - 0.24  2

Total  30

(i) The figure above is the grouped frequency distribution.

(ii) The number of days for which concentration of SO  

2

​

 is more than 0.11→0.12−0.16,0.16−0.20,0.20−0.24

∴ Total number of days =2+4+2=8 days.