In Q.5, Exercise 14.2, 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.


Total number of days recorded = 30 days

Number of days in which sulphur dioxide is in the interval 0.12 - 0.16 = 2


Hence,


Probability of days in which SO2 is in the interval 0.12 – 0.16 will be



12
1