The following table shows the number of traffic challans issued in the month of April by the traffic police: Find the 'mean' and 'mode' of the above…

Number of Challans	Number of days \(\displaystyle \left(f_{i}\right)\)	Class Mark \(\displaystyle \left(x_{i}\right)\)	\(\displaystyle f_{i} x_{i}\)
$\displaystyle 0$-$\displaystyle 10$	$\displaystyle 3$	$\displaystyle 5$	$\displaystyle 15$
$\displaystyle 10$-$\displaystyle 20$	$\displaystyle 5$	$\displaystyle 15$	$\displaystyle 75$
$\displaystyle 20$-$\displaystyle 30$	$\displaystyle 10$	$\displaystyle 25$	$\displaystyle 250$
$\displaystyle 30$-$\displaystyle 40$	$\displaystyle 9$	$\displaystyle 35$	$\displaystyle 315$
$\displaystyle 40$-$\displaystyle 50$	$\displaystyle 2$	$\displaystyle 45$	$\displaystyle 90$
$\displaystyle 50$-$\displaystyle 60$	$\displaystyle 1$	$\displaystyle 55$	$\displaystyle 55$
Total	\(\displaystyle \sum f_{i}=30\)		\(\displaystyle \sum f_{i} x_{i}=800\)

\[\begin{aligned} \text { Mean } & =\frac{800}{30} \\ & =\frac{80}{3} \text { or } 26.67 \text { or } 27 \text { (approx.) } \end{aligned} \] Modal class is $\displaystyle 20$-$\displaystyle 30$ \[\begin{aligned} \text { Mode } & =20+\frac{10-5}{2 \times 10-5-9} \times 10 \\ & =\frac{85}{3} \text { or } 28.3 \text { or } 28 \text { (approx.) } \end{aligned} \]