- #1
elmarsur
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Homework Statement
1. Suppose that the number of telephone calls an operator receives from 9:00 to 9:05 A.M. follows a Poisson distribution with mean 3. Find the probability that the operator will receive:
a. no calls in that interval tomorrow.
b. three or more calls in that interval the day after tomorrow.
2. Find the number of chocolate chips a cookie should contain
on the average if it is desired that the probability of a cookie
containing at least one chocolate chip be .99.
Thank you very much for any help!
Homework Equations
The Attempt at a Solution
Problem (1):
Noting probability of Poisson distribution with p, the number of calls with x, and the mean with m, we have
a) p=[(m^x)*(e^-m)]/x! = e^-m = e^-3
b) x=3 => p=1-p(x=2) = 1- [(m^2)*(e^-m)]/2! = 1- [(3^2)*(e^-3)]/2
Problem (2):
Preserving the notation above, p=.99 , x=1 =>
.99 = [(m^x)*(e^-m)]/x! = m*(e^-m)
If so, do I take ln of both sides to find m?
Thank you very much for any help!