In: Statistics and Probability
Snowfall in the City of Cleveland for the winter months (defined as January, February, and March) is distributed as a Poisson random variable, with an average of 5 inches per month.
What is the probability that there will be at least 13 inches of snow in the City of Cleveland next March? ANSWER: (Use only the appropriate formula and/or statistical table in your textbook to answer this question. Report your answer as to 4 decimal places, using conventional rounding rules.
What is the probability that there will be at least 7 but less than 11 inches of snow in the City of Cleveland next January? ANSWER: (Use only the appropriate formula and/or statistical table in your textbook to answer this question. Report your answer as to 4 decimal places, using conventional rounding rules.
What is the probability that there will be exactly 6 inches of snow in the City of Cleveland next January, February, and March combined? ANSWER: (Use only the appropriate formula and/or statistical table in your textbook to answer this question. Report your answer as to 4 decimal places, using conventional rounding rules.
µ = 5 inches per month
P(X = x) = e-µ * µx / x!
a) P(X > 13) = 1 - (P(X = 0) + P(X = 1) + P(X = 2) + ... + P(X = 12))
= 1 - (e-5 * 50 / 0! + e-5 * 51 / 1! + e-5 * 52 / 2! + ... e-5 * 512 / 12! )
= 1 - 0.998
= 0.0020
b) P(7 < X < 11) = P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10)
= e-5 * 57 / 7! + e-5 * 58 / 8! + e-5 * 59 / 9! + e-5 * 510 / 10!
= 0.2241
c) P(X = 6) = e-5 * 56 / 6! = 0.1462