Suppose you are conducting a survey regarding illicit drug u

Suppose you are conducting a survey regarding illicit drug use among teenagers in the Baltimore School District. You obtain a cluster sample of 12 schools within the district and sample all sophomore students in the randomly selected schools. The survey is administered by the teachers. How confident would you be in using this sample to make an inference about drug use among teenagers in the desired population?

Solution

I would not be very confident in using this sample to make an inference about the whole population because first, the schools were not selected randomly. They were a cluster sample, and this particular area may not be representative of the entire Baltimore area. Second, only sophomores were sampled. This will not give us a good idea about how kids of other grades feel about this topic. Third, the survey was administered by teachers. Students are not likely to be honest to teachers about drug use, so that is another source of biasness.

Hope this helps! :) Let me know if you have any other questions.