Question

In the following table, the toll paid by drivers and the number of vehicles is shown. Find the mean of the toll by 'assumed mean' method.
Toll (Rupees) : No. of vehicles
300-400 : 80
400-500 : 110
500-600 : 120
600-700 : 70
700-800 : 40

Answer 1

Step-by-step explanation:

Assume Mean a= 550

$\begin{tabular}{|l|l|l|l|l|}</p><p>\cline{1-5}</p><p>Class interval & Frequency(f_i) & Class mark(x_i) & d_i=a-x_i & d_if_i \\ \cline{1-5}</p><p>300-400 & 80 & 350 & -200 & -16000 \\ \cline{1-5}</p><p>400-500 & 110 & 450 & -100 & -11000 \\ \cline{1-5}</p><p>500-600 & 120 & 550 & 0 & 0 \\ \cline{1-5}</p><p>600-700 & 70 & 650 & 100 & 7000 \\ \cline{1-5}</p><p>700-800 & 40 & 750 & 200 & 8000 \\ \cline{1-5}</p><p>Total & 420 & & & -12000 \\ \cline{1-5}</p><p>\end{tabular}$

$mean = a + \frac{\Sigma \: d_if_i}{\Sigma \: f_i} \\ \\ = 550 + \frac{ - 12000}{420} \\ \\ = 550 - 28.57 \\ \\ = 521.43\:$

Mean =521.43 Rupees

Hope it helps you