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 number for information about some product. Suppose a random sample of $20$ consumers is contacted and interviewed about their buying habits.

Appendix A Statistical Tables

$($Round your answers to $3$ decimal places when calculating using Table A$\mathrm{.}2,$ eg$.0\mathrm{.}215.)$

a$.$ What is the probability that $11$ 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 $15$ of these consumers have called an $800$ or $900$ telephone number for information about some product?

c$.$ What is the probability that fewer than $8$ of these consumers have called an $800$ or $900$ telephone number for information about some product?