# Math Help - Statistics

1. ## Statistics

Let $N,X_1,X_2,...$ be independent random variables where N has a Poisson distribution with mean 3 while $X_1,X_2,...$ each has a Poisson distribution with mean 7.

Determine $E[\sum^{N}_{i=1} X_i]$ and also the variance of $\sum^{N}_{i=1} X_i$

Any help or hints would be most appreciated. Thanks.

2. Originally Posted by Len
Let $N,X_1,X_2,...$ be independent random variables where N has a Poisson distribution with mean 3 while $X_1,X_2,...$ each has a Poisson distribution with mean 7.

Determine $E[\sum^{N}_{i=1} X_i]$ and also the variance of $\sum^{N}_{i=1} X_i$

Any help or hints would be most appreciated. Thanks.
Read this thread: http://www.mathhelpforum.com/math-he...pectation.html

Also this one: http://www.mathhelpforum.com/math-he...variables.html