4. A recent survey showed that a majority of Americans plan on doing their holiday shopping online because they don’t want to spend money on gas driving from store to store (SOASTA

website, October 24, 2012). Suppose we have a group of 10 shoppers; 7 prefer to do their holiday

shopping online and 3 prefer to do their holiday shopping in stores. A random sample of 3 of

these 10 shoppers is selected for a more in-depth study of how the economy has impacted their

shopping behavior.

a. what is the probability that exactly 2 prefer shopping online?

b. what is the probability that the majority (either 2 or 3) prefer shopping online?