Question -
Answer -
Since, given data is not continuous, so we subtract 0.5 from the lower limit and add 0.5 in the upper limit of each class.
Now we first, find the class mark xt of each class and then proceed as follows:
∴ Assumed mean, a = 300.5
Class width, h = 200
and total observation, N = 50
By step deviation method,
= 300.5 + 200 x (1/50) x 14
= 300.5 + 56 = 356.5