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 800 or 900 telephone numbers for information about some 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 800 or 900 telephone number for information about some product?
b. What is the probability that more than 20 of these consumers have called an 800 or 900 telephone numbers for information about some product?
c. What is the probability that fewer than 10 of these consumers have called an 800 or 900 telephone number for information about some product?