Refer to Exercise 100.

a. Justify why D can be approximated by a Normal distribution.

b. Use a Normal distribution to estimate the probability that 30 or more adults in the sample have more debt than savings.

Exercise 100.

According to financial records, 24% of U.S. adults have more debt on their credit cards than they have money in their savings accounts. Suppose that we take a random sample of 100 U.S. adults. Let D = the number of adults in the sample with more debt than savings.