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.

Answer

The mean fo toll is Rs. `521.43`.

Explanation

Let us take 550 as the assumed mean.
Then `A = 550` and deviation `d_(i) = x_(i) - A = x_(i) - 550`

Here , `Sigma f_(i)d_(i) = - 12000, Sigma f_(i) = 420`
` barb = (Sigmaf_(i)d_(i))/(Sigmaf_(i)) = (-12000)/(420) approx - 28.57`
Mean `barX = A + bard`
` = 550 + (-28.57)`
` = 550 - 28.57 = 521.43`.