A Gallup telephone poll of 1240 teens conducted in 2001 found that boys were more likely than girls to play computer games, by a margin of 77% to 65%. Equal numbers of boys and girls were surveyed.
a) What kind of sampling design was used?
b) Give a 95% confidence interval for the difference in game playing by gender.
c) Does your confidence interval suggest that among all teens a higher percentage of boys than girls play computer games?