Question

Consider the discrete probability distribution to the right. Complete parts a and b below.

Outcome	Probability
1	0.17
2	0.25
3	0.25
4	0.33

Mean of this distribution = 2.74

Calculate the standard deviation of this distribution.

Answer 1

solution:

Outcome	Probability
1	0.17
2	0.25
3	0.25
4	0.33

Solution :

Mean = = X * P(X)

= 1 * 0.17 + 2 * 0.25 + 3 *0.25 + 4 * 0.33

= ( 0.17+ 0.50 + 0.75+ 1.32)

= 2.74

Standard deviation =

=X 2 * P(X) - 2

=  [ 12   *0.17 + 22 * 0.25+ 32 * 0.25+ 42 * 0.33]

= [( 0.17+ 1 +2.25 +5.25 ) )]

= 8.7

=2.95

standard deviation of this distribution.is 2.95