Been a while since i dealt with poisson distribution any help is appreciated =]
Find probability that
i) exactly 6 are sold in a randomly chosen week
ii) exactly 6 are sold in each of 3 randomly chosen weeks
iii) exactly 18 are sold in a randomly chosen 3 week period
ok for i I use the formula (e^-λ8λ^X) / X!
which gives me (e^-5 8 5^6) / 6!
= 0.1462 (4 d.p.)
now for part ii is it the above answer cubed?? giving 3.1264 x10^-3
really cant remember how to do part iii