Which of the following statements are true?
I. The mean and the variance of a Poisson distribution are equal.
II. A Poisson distribution needs two numbers, $n$ and $p$ , to describe it.
III. A Poisson variable can take any of the values 0, 1, 2, 3, …
IV. It suits rare events among a large number of chances.

All four: I, II, III and IVCorrect answerYour answerI, III and IV onlyCorrect answerYour answerI and III onlyCorrect answerYour answerII, III and IV onlyCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

Mean = variance = $\lambda$ (I), the values run 0, 1, 2, … with no upper limit (III), and it models rare events (IV).
II is false: a Poisson distribution has one parameter, $\lambda$ ; $n$ and $p$ belong to the binomial.

Concept: Facts about the Poisson distribution
Typical timeTypical: 120 s
Your timeYours: —

The rule this testsThe Poisson distribution

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Ten questions from Binomial & Poisson Distributions, at your own pace.

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