Computer gaming. In order to effectively market electronic games, a manager wanted to know what age group of boys played more. A survey in 2006 found that 154 of 223 boys aged 12–14 said they “played computer or console games like Xbox or PlayStation . . . or games online.” Of 248 boys aged 15–17, 154 also said they played these games.

a) Is there evidence that the percentage of boys who play these types of games is different in the two age groups?

b) Give a 90% confidence interval for the difference in proportions.