Question

An increasing number of consumers believe they have to look out for themselves in the marketplace. According to a survey conducted by the Yankelovich Partners for USA Weekend magazine, 60% of all consumers have called an information line for a product. Suppose a random sample of 25 consumers is contacted and interviewed about their buying habits.

a. What is the probability that 15 or more of these consumers have called an information line for a product?

b. What is the probability that more than 20 of these consumers have called an information line for a product?

c. What is the probability that fewer than 10 of these consumers have called an information line for a product?

Answer 1

Let X be the random variable denoting the number of consumers have called an information line for a product

So X follows a binomial distribution with parameters

n = 25

p = 0.6

a)

= 0.5858

b)

= 0.0024

c)

= 0.0132

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