Freshman binge drinking. A survey of drinking in college students found 1802 binge drinkers among 5266 U.S. freshman completing a survey.

x

(a) The prevalence of binge drinking in this sample is or 34.2%. Assume that the data represent an SRS of U.S. freshman. Also assume that the responders provided accurate information. Using this information, determine the prevalence of binge drinking in U.S. freshman with 95%

confidence.

(b) Calculate the 99% confidence interval for the prevalence.

Interpret the result.

(c) A study from the late 1990s found that 20% of freshman engaged in binge drinking. Assume that 20% is an accurate and reliable estimate for the prevalence of binge drinking in the 1990s. Do the current data provide reliable evidence of an increase in the prevalence of binge drinking since the 1990s?