Problem 4 Use the information below to answer questions 8 and 9. In an effort to estimate the annual income for new graduates, data were collected from 100 new graduates over a 1-year period. Assume a population standard deviation of $2,000. If the sample mean is $15,000, what is the 95% confidence interval for the population mean? Select one: a. $14,534 to $15,466 b. $14,603 to $15,396 c. $14,668 to $15,332 d. $14,590 to $15,410 e. $14,608 to $15,392