For Exercises 8.1 and 8.2, see page 419; for 8.3 and 8.4, see page 421; for 8.5 to 8.7, see page 423; for 8.8 to 8.11, see pages 425–426; for 8.12, see page 426; for 8.13 and 8.14, see page 429; and for 8.15 and 8.16, see page 431.

Question 8.4

8.4 Customer growth and retention strategy

Refer to Exercise 8.2 (page 419).

  1. Find , the standard error of .
  2. Give the 95% confidence interval for in the form of estimate plus or minus the margin of error.
  3. Give the confidence interval as an interval of percents.