For Exercises 6.23 to 6.25, see page 304; for 6.26 and 6.27, see pages 305–306; for 6.28 to 6.30, see page 309; for 6.31 and 6.32, see page 311; and for 6.33, see page 313.
6.28 Average amount paid for college.
Refer to Example 6.10 (pages 307–308). The average annual amount the families paid for college was $20,902.9 If the population standard deviation is $7500, give the 95% confidence interval for , the average amount a family pays for a college undergraduate.