6. For borrowers with good credit scores, the mean debt for revolving and installment accounts

is $15,015 (BusinessWeek, March 20, 2006). Assume the standard deviation is $3540 and that

debt amounts are normally distributed.

a. What is the probability that the debt for a borrower with good credit is more than $18,000?

b. What is the probability that the debt for a borrower with good credit is less than $10,000?

c. What is the probability that the debt for a borrower with good credit is between $12,000 and

$18,000?

d. What is the probability that the debt for a borrower with good credit is no more than

$14,000?