In Example 4f, we showed that the covariance of the multinomial random variables Ni and Nj is

Question:

In Example 4f, we showed that the covariance of the multinomial random variables Ni and Nj is equal to −mPiPj by expressing Ni and Nj as the sum of indicator variables. We could also have obtained that result by using the formula
Var(Ni + Nj) = Var(Ni) + Var(Nj) + 2 Cov(Ni, Nj)
(a) What is the of Ni + Nj?
(b) Use the preceding identity to show that Cov(Ni, Nj) = −mPiPj.
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...