In a survey, 63% of Americans said they own an answering machine. If 14 Americans are selected at random, find the probability that exactly 9 own an answering machine.

Answer 1

Use a binomial probability function table. Values to look up are: p = .63, n = 14, and x = 9.

Or...

Calculate it by hand:
P(x) = (nCx)(p^x)[q^(n-x)]
...where q = 1 - p.

Answer 2

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