Calculate the arithmetic mean for the following data Using step deviation method.

In step deviation method, we divide deviation by the width of the class intervals in order to simplify the calculation.

Here, we shall assume a mean from the given x_i’s. Let the assumed mean (A) be 35.

Also,

Where, A = assumed mean = (here) 35

& c = width of the class intervals = (here) 10

Construct the following table:

Using these values, we can find the arithmetic mean of the following data.

Arithmetic mean is given by

⇒

⇒ Mean = 35 – 7

⇒ Mean = 28

Thus, arithmetic mean of the following data is 28.