depending on the moment generating function of the random variable X : M(t)=e^(t^2 ) :find

1. p(x=2)

2.find the mean of X

3. FIND THE VARIANCE of -2x

4.find the the second moment about the origin

i don't know how i starting ??(Headbang)

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- August 6th 2008, 10:36 AMflower3please>>>>
depending on the moment generating function of the random variable X : M(t)=e^(t^2 ) :find

1. p(x=2)

2.find the mean of X

3. FIND THE VARIANCE of -2x

4.find the the second moment about the origin

i don't know how i starting ??(Headbang) - August 6th 2008, 07:15 PMmr fantastic
- August 6th 2008, 07:51 PMmr fantastic
Note that the normal distribution with mean and variance has the moment generating function .

Compare this with the given moment generating function and you see that X must follow a normal distribution with and variance .

This gives you a way of checking the answers to 2. and 3.

It also lets you calculate Pr(a < X < b) were it to be asked. - August 7th 2008, 03:51 AMflower3
(Heart)thank you i think you're the best "mr fantastic"(Clapping)

- August 7th 2008, 04:00 AMflower3
wait >>>>>>

you say the distribution is continuous :

when i find the variance by the 1st and the 2nd derivative for moment generating function i get var(x)=0 but you say that is = 2 how???(Crying)(Crying) - August 7th 2008, 04:09 AMmr fantastic
- August 7th 2008, 06:13 AMflower3
i'm so sorry i solve it before i open my mail and see the solution >>>

i forgot that the derivative for 2te^(t^2 ) is equal to "derivative for two multiply function " so the answer is false >>>>>

but i solve it >>>>>then i verify from your saying

thank you>>>>you're a nice man(Heart) - August 7th 2008, 06:16 AMflower3
- August 7th 2008, 03:28 PMmr fantastic
- August 8th 2008, 02:09 AMflower3thank you !(Talking)

all people maybe miscalculate since we're human(Itwasntme)