1 A personal trainer wishes to study the effect of cardio exercise versus weight lifting on resting heart rate. He randomly selects five people at the gym who self identify as exclusively doing cardio, and he randomly selects five more people at the gym who self identify as exclusively doing weight lifting. He then measures and compares the two groups' resting heart rates. Is this an experiment or an observational study? A. This is an experiment because the subjects are actively doing something (exercising). B. This is an observational study because the personal trainer is collecting data on the subjects. C. This is an experiment because the personal trainer is comparing two distinct groups to each other. D. This is an observational study because the personal trainer did not assign people to do one type of exercise or the other. QUESTION 2 A natural remedies company is developing a new herbal remedy for colds. They pay participants to contact them when they feel like they are getting a cold, at which point the participants are promptly given a pill to take for the next three days. Half the participants are given the active treatment, the herbal remedy, while the other half are given a placebo that looks exactly like the active treatment but contains no medicine. The natural remedies company then compares the number and severity of symptoms in the two groups. Is this an experiment or an observational study? A. This is neither an observational study nor an experiment because there is no way of knowing if the herbal remedy actually had an effect on the particpants' colds. B. This is an observational study because the natural remedies company is observing the number and severity of symptoms in the participants. C. This is an experiment because the natural remedies company is assigning participants to a treatment. D. This is an experiment because two groups are being compared. QUESTION 3 Participants in a memory study record everything they eat for two years. They choose what they eat. At the end of the two years, a medical researcher records the participants' performance on a memory test and finds that people who ate more fish tended to have better short term memory. Can we conclude that eating more fish leads to better short term memory? A. No, this was an observational study, and causation cannot be determined from an observational study. There could be a confounding variable. B. Yes, this is an experiment because the researcher followed the participants for two years. Causation can be determined from a randomized experiment. C. Yes, it is clear that participants who ate more fish had better short term memory, so the cause and effect relationship is obvious. D. No, the study did not last long enough to determine if there is a cause and effect relationship between fish consumption and short term memory. OUESTION 4 What is the purpose of a control group in an experiment? A. The control group acts as a baseline to compare treatment groups against. B. Having a control group minimizes the effect of all other variables except the explanatory variable. C. Comparing the treatment group against the control group helps researchers quantify the magnitude of the effect of the treatment. D. All of the above QUESTION 5 A first grade teacher wishes to see if her sight word system of teaching helps students learn to read faster. She uses her sight word system when teaching all of her students throughout the school year, then compares their reading level at the end of the year to their reading level at the beginning of the year. She finds a big improvement in reading abilities and attributes it to her sight word system of teaching. What is the biggest problem with this study? A. The teacher should have tried using her sight word system several years in a row to have more data. B. There are no problems with this study. As long as the teacher carefully measured the student's scores at the beginning and end of the year, she can conclude that sight word teaching method helps students improve their reading level. C. The teacher should have had someone else teach the students with her sight word method to make sure others can recreate her results. D. There was no control group to compare the students who learned using her sight word system against. The students may have all improved in reading anyway over the course of a year, regardless of whether they used her sight words system or not