**Direct method**

**x dash (put the dash over x) = ∑x / N**

where x dash :- arithmetic mean

∑x :- sum of total observation or item

N :- total no. of items

__Short-cut method__

**x dash = A+∑d / N**

where x dash = arithmetic mean

A = assumed mean

d = x - A i.e., deviations of variables from assumed mean

∑d = sum of deviations of variables from assumed mean

N = total no. of items

__Step-deviation method__

**x dash = (x - A) / C**

where x dash = arithmetic mean

∑d = x - A i.e., deviations of variables from assumed mean

d' = (x - A) / C i.e., step deviations

∑d' = sum of step deviation

C = common factor

N = total no. of items

*and if u hav further doubts like where frm did the d' come along den inbox me !! :)*