random var. X is -1, 0, 1 w/ equal probability (check ans)

[zorro]

Question :
X is a random variable which takes 3 values -1,0,1 with equal probability i.e. P(x=-1) = P(X=0) = P(X=1) = 1\3
Find E(X) and Var(X)
Solution :
E(X) = 0 _{(is this correct?)}

var(X) = 0 _{(is this correct?)}

[Martingale]

Question :
X is a random variable which takes 3 values -1,0,1 with equal probability i.e. P(x=-1) = P(X=0) = P(X=1) = 1\3
Find E(X) and Var(X)
Solution :

ok...

E(X) = 0 _{(is this correct?)}

Yes

var(X) = 0 _{(is this correct?)}

No

[zorro]

Please can u tell what is wrong


My work ........
E(X) = 0

₁ = 0

₂= 2/3

² = 2/3

var(X) = ₂ - ² = 2/3 - 2/3 = 0

[Martingale]

Please can u tell what is wrong


My work ........
E(X) = 0

₁ = 0

₂= 2/3

² = 2/3

var(X) = ₂ - ² = 2/3 - 2/3 = 0

[zorro]

Please can u tell what is wrong


My work ........
E(X) = 0

₁ = 0

₂= 2/3

² = 2/3

var(X) = ₂ - ² = 2/3 - 2/3 = 0

Thanks !!!