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 a follows :

(i) Make a grouped frequency distribution table for this data with class-intervals as `0.00-0.04, 0.04-0.08` and so on.
(ii) For how many day's was the concentration of sulphar dioxide more than 0.11 parts per million (ppm)?

Explanation

(i) We condense the given data into group like `0.00-0.04, 0.04-0.08,…. 0.20-0.24.` (since, our data is form 0.01 to 0.22). The class width in this case is 0.04.
Now, the given data can be condensed in tabular form as follows:

(ii) The concertration of sulphar dioxide was more than 0.11 ppm for `2+4+2=8` days (by table).