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:
$\begin{array}{cccccc}0.03& 0.08& 0.08& 0.09& 0.04& 0.17\\ 0.16& 0.05& 0.02& 0.06& 0.18& 0.20\\ 0.11& 0.08& 0.12& 0.13& 0.22& 0.07\\ 0.08& 0.01& 0.10& 0.06& 0.09& 0.18\\ 0.11& 0.07& 0.05& 0.07& 0.01& 0.04\end{array}$
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

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	$30$

Number of days for which $S{O}_2$ concentration was in the interval of $0.12-0.16=2$
Total bags $=30$
P $=\frac{2}{30}=\frac{1}{15}$