Question

Question 8
The mileage (km per litre) of 50 cars of the same model was tested by a manufacturer and details are tabulated as given below
$\begin{array}{ccccc}Mileage\left(km{L}^{-1}\right)& 10-12& 12-14& 14-16& 16-18\\ Numberofcars& 7& 12& 18& 13\end{array}$
Find the mean mileage.
The manufacturer claimed that the mileage of the model was $16km{L}^{-1}.$ Do you agree with this claim?

Answer 1

$\begin{array}{cccc}Mileage\left(km{L}^{-1}\right)& Classmarks\left(x_i\right)& Numberofcars\left(f_i\right)& f_i{x}_i\\ 10-12& 11& 7& 77\\ 12-14& 13& 12& 156\\ 14-16& 15& 18& 270\\ 16-18& 17& 13& 221\\ Total& & \sum f_i=50& \sum f_i{x}_i=724\end{array}$
Here, $\sum f_i=50$
and $\sum f_i{x}_i=724$
$\therefore$ Mean $\overline{x}=\frac{\sum f_i{x}_i}{\sum f_i}$
$=\frac{724}{50}=14.48$
Hence, mean mileage is $14.48km{L}^{-1}.$
No, the manufacturer is claiming mileage $1.52km{h}^{-1}$ more than average mileage.