For Exercise 6.1, see page 289; for 6.2 and 6.3, see page 293; for 6.4, see page 294; for 6.5, see page 295; for 6.6 and 6.7, see page 297; and for 6.8, see page 298.

Question 6.8

6.8 Find a probability.

Refer to Example 6.8. Find the probability that the mean time between text messages is less than 16 minutes. The exact probability is 0.6944. Compare your answer with the exact one.