Dogs A census by the municipal dog control officer found that 18% of homes kept one dog as a pet, 4% had two dogs, and 1% had three or more. If a salesperson visits two homes selected at random, what’s the probability he encounters

a) no dogs?

b) some dogs?

c) dogs in each home?

d) more than one dog in each home? Courtesy of Richard De Veaux 33.

When to stop? You play a game that involves rolling a die. You can roll as many times as you want, and your score is the total for all the rolls. But . . . if you roll a 6, your score is 0 and your turn is over. What might be a good strategy for a game like this? You attempted to devise a good strategy by simulating several plays to see what might happen. Let’s try calculating a strategy.

a) It can be shown that on average, a 6 would appear for the first time on the 6th role. So, roll one time less than that. Assuming all those rolls were not 6s, what’s your expected score?

b) What’s the probability that you can roll that many times without getting a 6?