Method of Moment Generating Function Help

[wannabe92]

Let X1 be a binomial random variable with n1 trials and p1 = 0.2 and X2 be an independent
binomial random variable with n2 trials and p2 = 0.8. Find the probability function of
Y = X1 + n2 – X2.
Exactly how does one calculate the mgf of (n2 - X2)?

 

[Ray Vickson]

Let X1 be a binomial random variable with n1 trials and p1 = 0.2 and X2 be an independent
binomial random variable with n2 trials and p2 = 0.8. Find the probability function of
Y = X1 + n2 – X2.
Exactly how does one calculate the mgf of (n2 - X2)?

If X2 counts the number of successes, what does n2 - X2 count?

RGV