1. ## geometric m.g.f.

what does the second derivative of the geometric moment generating function yield? is it 1/p^3

2. Originally Posted by statworm31
what does the second derivative of the geometric moment generating function yield? is it 1/p^3
Do you know the mgf? Do you know how to differentiate? Where are you stuck?

3. th m.g.f. for a geomeric distribuion is pe^t/1-e^tq the first dervative is
(pe^t)(1-e^tq)-(pe^t)(-e^tq)/(1-e^tq)^2 I need the second derivative in order to find v(y) and that is where I am stuck

4. Originally Posted by statworm31
th m.g.f. for a geomeric distribuion is pe^t/1-e^tq the first dervative is
(pe^t)(1-e^tq)-(pe^t)(-e^tq)/(1-e^tq)^2 I need the second derivative in order to find v(y) and that is where I am stuck
There is a difference between being stuck because you just don't know what to do, and being stuck because what you have to do is tedious and requires great care. In all honesty I think you're 'stuck' falls into the latter category. You just have to apply the quotient rule and put in all the steps. I think you can do that task just as well as I can - probably better since you will be motivated.

If you genuinely cannot do it, please say so. Preferably, show where abouts in the calculation you were able to get to.