Use this information to answer questions 15 19. Researchers who wanted to see if drinking grape juice could help people lower their blood pressure got 120 nonsmokers to volunteer for a study. They measured each person's blood pressure and then randomly divided the subjects into two groups. One group drank a glass of grape juice every day while the other did not. After sixty days the researchers measured everyone's blood pressure again. They reported that differences in changes in blood pressure between the groups were not statistically signicant. 15. Was this an experiment or an observational study? Explain. a. observational; observed 120 non-smokers b. observational; volunteers caused this study to be biased 'v c. experimental; treatments were applied d. experimental; one groupfall non-smokers 16. What is meant by \"not statistically signicant\" in this context? a. The differences were large since this lasted 60 days. b. There were not many subjects involved. c. Only non-smokers were included so this could not be expanded to the general population. d. The results were small enough that they could easily be attributed to variability, not the grape juice. 1?. Why did the researchers randomly assign the subjects to the groups? . a. This equalizes the effects of variables for which were not controlled. b. This was easier. c. They could keep track of who was in which group easier. d. Not everyone liked grape juice. '18. Why did they have a group that was not drinking grape juice? a. They did not like grape juice b. They needed a control groupIto compare with the treatment group. c. This was a placebo since they all needed something. at. In order for the experiment to be valid. it needed to be confounded. 19. Why did the researchers study only non-smokers? a. They wanted to limit the number of subjects in the experiments. b. That would result in variability. c. The smokers were used as a control. d. Smoking tends to affect blood pressure. It might have confounded the results