Question

Find the population variance and standard deviation for the set of data:   13, 7, 21, 4, 15, 23, 7, 6.

Answer 1

Solution:

Mean :

= (X) / n

= ( 13+7+21+4+15+23+7+6 ) / 8

= 96 / 8

= 12

Population Variance :

= ( X -  )² / n

= ( 13 - 12 )² + ( 7 - 12 )² + ( 21 - 12 )²​​​​​​​ + ( 4 - 12 )²​​​​​​​ + ( 15 - 12 )²​​​​​​​ + ( 23 - 12 )²​​​​​​​ + ( 7 - 12 )²​​​​​​​ + ( 6- 12 )²​​​​​​​

= 362 / 8

= 45.25

Population standard deviation :

= ( X -  )² / n

= Variance.

= 45.25

= 6.7268