I am getting stuck on these questions.

One way MSNBC solicits the opinions of its news consumers is through the organization's online Speak Out surveys. Using social media and its television and radio news shows, MSNBC encourages its news consumers to go online and respond to various opinion polls about trending topics. Typically the polls remain open. In one ongoing Speak Out poll, MSNBC asks whether marijuana should be legalized, decriminalized, or illegal. As of May 10th, 2015, more than 26,000 people had responded to the poll, and 77% indicated that marijuana should be legalized. [ Choose] The math department faculty at a large university wanted to know what portion of the student body believes students should be able to enroll in any math class without meeting a prerequisite. The statistics department offered to cooperate in conducting a survey, and a simple random sample of 500 students was selected from all the students enrolled in statistics classes. A survey form was sent by email to these 500 students and 236 responded. To identify the population and the sample for this study, label each item on the left with a term on the right. All students at the . . [ Choose] V univerSIty 236 students who responded to the email survey [ Choose] V The math Observation; V department recently purchased new learning software for their freshman math classes. The instructors want to use the learning software instead of a textbook. So they decide to study the effectiveness of the software. First they test the skills and concept mastery for a number of the freshman math students. Then they randomly divide the students into two groups. One group uses the learning software for a particular lesson and the other group uses the regular textbook. Then the instructors retest all of the students and compare the improvement in the skills and concept mastery for the two groups. Label each study as either an observational study or an experiment. From December 2007 through March [Choose] V 2012, researchers at the University of Pittsburgh studied a new medication to treat osteoporosis in frail elderly women. The researchers administered a daily dose of the medication or a placebo by injection along with calcium and vitamin D supplements. Then the researchers measured the hip and spine bone density of each patient at 12 and 24 months. Results were published in the Journal of the American Medical Association (JAMA) in April 2015