According to a survey 60% of all consumers have called an 800 or 900 phone number for information about some product. Suppose a random sample of 25 consumers is called and interviewed about their buying habits.
1.What is the probability that 15 or more of these consumers have called an 800 or 900 phone number for information about some product?
p = 60% = 0.60, q = 1 - p = 0.40, n = 25
(a) Mathematical Solution
P(r) = C(n, r) p^r q^(n - r)
P(15 or more) = P(15) + P(16) + P(17) ...
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