7. Radio-Listening Trends. The Arbitron Corporation tracks radio-listening trends among demographic groups. In a survey, 240 teens ages 12–17 listened to pop contemporary hit radio stations, whereas 170 teens listened to alternative radio stations. Also, 250 young adults ages 18–24 listened to pop contemporary hit radio stations, whereas 260 young adults listened to alternative radio stations. Test whether age and radio station type are independent, using level of significance .