Question

In the following table, the toll paid by drives and the number of vehicles is shown. Find the mean of the toll by assumed mean method.

Toll (Rupees)	$300-400$	$400-500$	$500-600$	$600-700$	$700-800$
No. of vehicles	$80$	$110$	$120$	$70$	$40$

Answer 1

$CI$	$Class-mark$ $x_i$	$d_i=x_i-A$	$f_i$	$f_i{d}_i$
$300-400$	$350$	$-200$	$80$	$-16000$
$400-500$	$450$	$-100$	$110$	$-11000$
$500-600$	$550=A$	$0$	$120$	$0$
$600-700$	$650$	$100$	$70$	$7000$
$700-800$	$750$	$200$	$40$	$8000$
			$\sum f_i=420$	$\sum f_i{d}_i=-12000$

$\overline{x}=A+\frac{\sum f_i{d}_i}{\sum f_i}$

$=550-\frac{12000}{420}$

$=550-28.57$

$=521.43$

$\therefore$ Mean of toll is $Rs.521.43$

Hence, this is the answer.