Question

4) - 6) Thickets. The following discrete probability distribution represents the number of speeding tickets in the past 12 months  

X 0 1 2 3

P(X) 0.85 0.11 0.02 0.02   

Compute the mean.

0.37

1.5

0.25

0.21

X 0 1 2 3

P(X) 0.85 0.11 0.02 0.02

Compute the variance

0.3249

0.57

0.3258

0.3259

  X 0 1 2 3

P(X) 0.85 0.11 0.02 0.02

Compute the standard deviation.

0.5709

0.37

0.5710

0.58

Answer 1

Solution :

x	P(x)	x * P(x)	x2 * P(x)
0	0.85	0	0
1	0.11	0.11	0.11
2	0.02	0.04	0.08
3	0.02	0.06	0.18
Sum	1	0.21	0.37

4)

Mean = = X * P(X) = 0.21

5)

Variance = X ² * P(X) - ² = 0.37 - 0.21² = 0.3259

6)

Standard deviation = = 0.3259 = 0.5710