Question

The following table provides a probability distribution for the random variable y f(y) 2 0.10 5 0.30 0. 30 0.30 a. Compute E(y) (to 1 decimal). b./Compute Var(y) and o (to 2 decimals). Var(y)

Answer 1

Y	P(Y)	Y*P(Y)	Y² * P(Y)
2	0.10	0.200	0.4000
5	0.30	1.500	7.5000
6	0.30	1.800	10.8000
9	0.30	2.700	24.3000

	P(Y)	Y*P(Y)	Y² * P(Y)
total sum =	1	6.2	43.00

a)

E[Y] = ΣY*P(Y) =            6.2

b)

E [ Y² ] = ΣY² * P(Y) =            43.0000
          
variance = E[ Y² ] - (E[ Y ])² =            4.56
          
std dev,σ = √(variance) =           2.14

Answer 2

a.  

 

b.  

Varience
St Dev