a. Sixty patients with carpal tunnel syndrome are randomly divided Into two groups. One group is treated weekly with both acupuncture and an exercise regimen. The other is treated weekly N with the exact same exarclse regimen, but no acupuncture. After 1 year, both groups are questioned about their level of pain due to carpal tunnel syndrome. Determine whether the study depicts an observational study or an experimental study. A college ofcial divides the student population into ve classes: freshman, sophomore, junior, senior and graduate student. The official takes a simple random sample from each class and asks the members' opinions regarding student services. Determine the type of sampling used. The presider of a guest-lecture series at a university stands outside the auditorium before a lecture begins and hands every fth person who arrives, beginning with the third, 3 speaker evaluation survey to be completed and returned at the end of the program. Determine the type of sampling used. Suppose you are conducting a survey regarding the sleeping habits of students. From a list of registered students, you obtain a simple random sample of 150 students. One survey question is "How much sleep do you get?" Determine the type of bias in the survey. Think about a remedy, if any