Decide if the study is an observational study or an experiment. 100 students were followed over a 6-month period. The number of students who took Echinacea (a herbal supplement) and the number who developed colds were recorded.
a. Observational Study
b. Experiment
Q. 2Decide if the study is an observational study or an experiment. A study compared a group of men who had heart attacks with a similar group of controls. The proportion of men with male pattern baldness was compared between the two groups.
a. Observational Study
b. Experiment
Q. 3Decide if the study is an observational study or an experiment. A medicine to remove the redness in eyes was tested in a group of 100 students. Each student took the medicine in one eye and a placebo in the other eye. The eye (left or right) that received the placebo was decided by flipping a coin.
a. Observational Study
b. Experiment
Q. 4Decide if the study is an observational study or an experiment. Thirty-six students were randomly assigned to listen to Mozart (18 students) or a relaxation tape (18 students). The IQ of the students were measured afterwards.
a. Observational Study
b. Experiment
Q. 5Decide if the study is an observational study or an experiment. A study compared the IQ from children whose mothers smoked to the IQ from children whose mothers didn't smoke.
a. Observational Study
b. Experiment
Q. 6Decide if the study is an observational study or an experiment. A biologist measured the increasing amounts of phosphorus in Lake Erie and observed a decreasing number of lake trout over a 5-year period.
a. Observational Study
b. Experiment
Q. 7Decide if the study is an observational study or an experiment. Twenty blue-fin tuna were randomly assigned to two tanks of water, 10 tuna in each tank. One tank was polluted with methyl mercury, while the other tank was not polluted. The survival times of the fish in the two tanks were compared.
a. Observational Study
b. Experiment