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:

0.03 0.08 0.08 0.09 0.04 0.17


0.16 0.05 0.02 0.06 0.18 0.20


0.11 0.08 0.12 0.13 0.22 0.07


0.08 0.01 0.10 0.06 0.09 0.18


0.11 0.07 0.05 0.07 0.01 0.04


(i) Make a grouped frequency distribution table for this data with class intervals as0.00 - 0.04, 0.04 - 0.08, and so on.


(ii) For how many days, was the concentration of sulphur dioxide more than 0.11parts per million?

(i) The data with class interval 0.00-0.04, 0.04-0.08 and so on is represented in the table as:


CONCENTRATION OF SO2 IN AIR


(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




(ii) 2 + 4 + 2 = 8


Hence, 8 days have the concentration of sulphur dioxide more than 0.11 parts per million


8