The standard deviation of the numbers 22 ,   26 ,   28 ,   20 ,   24 ,   30 is

The standard deviation of the numbers 22, 26, 28, 20, 24, 30 is
  1. 2
  2. 2.4
  3. 3.24
  4. 3.42

Solution

We know that

S.D=xi-μ2N 

where, 

μMean

NNumber of terms

xiterms

Now,

μ=22+26+28+20+24+306

μ=1506=25

Now, 

xi xi-μ2
22 22-252=9
26 26-252=1
28 28-252=9
20 20-252=25
24 24-252=1
30 30-252=25

Therefore, xi-μ2=70

S.D=706=3.42

Asked in: AP EAMCET 2018 (25 Apr Shift 1)

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