Question

Find the variance of the following data. Round your answer to one decimal place.

x	7	8	9	10	11
P(X=x)	0.1	0.1	0.3	0.2	0.3

Answer 1

Solution :

Mean = = X * P(X)

= 7 * 0.1+ 8 * 0.1 + 9* 0.3+ 10 * 0.2 + 11* 0.3

= ( 0.7+ 0.8 + 2.7+2+3.3 )

= 9.5

variance= 2

=X 2 * P(X) - 2

=  [    7 2* 0.1+ 8 2* 0.1 + 92* 0.3+ 102 * 0.2 + 112* 0.3] -9.52

=  [( 4.9+ 6.4 +24.3 + 20+36.3) )]-90.25

= 91.9-90.25

=1.65

variance= 2=1.7

answered by: anonymous