Truthfulness in online profiles. Many teens have posted profileson a social-
networking website. A sample survey in 2007 asked a random sampleof teens
with online profiles if they included false information in theirprofiles. Of 170
younger teens (aged 12 to 14), 117 said yes. Of 317 older teens(aged 15 to 17),
152 said yes.
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(a) Do these samples satisfy the guidelines for the large-sampleconfidence
interval?
(b) Give a 95% confidence interval for the difference between theproportions
of younger and older teens who include false information in theironline
profiles.
