Given: Group of 6 people having weights 45,50,65,72,63,35 (in kgs) Formula Used: Mean=
sumofobservations
numberofobservations
Standard deviation =√[
(Σx2)
N
] , where Σx2 } is the summation of the square of deviation of all observations from Mean. Calculation; Sum of all observations =(45+50+65+72+63+35)=330 Mean =
330
6
= 55
Observations
Mean
Deviation from Mean (x)
Square
of deviation (x2)
45
55
-10
100
50
55
-5
25
65
55
-10
100
72
55
-17
289
63
55
-8
64
35
55
-20
400
Σx2=(100+25+100+289+64+400) ⇒Σx2=978 Standard Deviation (σ)=√(
978
6
)=√163 ∴ The standard deviation of given data set of weights is √163 .