Question

Compute the (sample) variance and standard deviation of the data sample. (Round your answers to two decimal places.)

−1, 7, 7, 5, 12

variance	22
standard deviation	?

Answer 1

Solution :

Given that,

x	x2
- 1	1
7	49
7	49
5	25
12	144
x = 30	x2 = 268

The  sample variance S²

  S² = ( x² ) - (( x )² / n ) / 1 -n )

= ( 268 (- (30 )² / 5 ) /4

   = ( 268 -180 ) 4

=88 /4

= 22

The  sample variance S² = 22

The sample standard is S =   The  sample variance S²

=   22

= 4.6904

The sample standard is S = 4.69