推 secondheart:因為每個人工作是獨立的 10/25 20:09
Let the number of jobs arriving at a shop in a 1-hour period
be a possion random variable N with mean m=4
Each job requires Xi seconds to complete, where Xj's are independent
and identically distributed random variables that are equal to 3 minutes
or 6 minutes with equal Pr.
Find the Pr generating funtion E[z^w]
Sol:
E[z^w]=E[ E[z^w|N] ]=E[ (0.5z^3+0.5z^6)^N ]
到這裡就不太懂了，為什麼會是N次方?
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