Answers

2015-09-10T21:14:48+05:30
For direct method formula= sigma fixi÷sigma fi
step deviation : sigma fiui×h÷sigma fi +a here ui=di÷a
short cut method : sigma fidi÷sigma fi+a here di=xi-a
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wht is sigma? do u mean summation ?
its submission
dis is the maths formula for these methods ryt?
The Brainliest Answer!
2015-09-10T21:43:39+05:30
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 !! :)
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