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

Posted: Tue Jun 29, 2010 2:27 am
by 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?)

Re: random var. X is -1, 0, 1 w/ equal probability (check an

Posted: Tue Jun 29, 2010 3:53 am
by 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

Re: random var. X is -1, 0, 1 w/ equal probability (check an

Posted: Wed Jun 30, 2010 2:27 am
by 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

Re: random var. X is -1, 0, 1 w/ equal probability (check an

Posted: Wed Jun 30, 2010 4:48 am
by 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

Re: random var. X is -1, 0, 1 w/ equal probability (check an

Posted: Sun Jul 04, 2010 4:03 pm
by 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 !!! :clap: