Clinical Trial of Bystolic. In clinical trials of the drug Bystolic used to treat hypertension (high blood pressure), 677 Bystolic users were observed for adverse reactions. It was found that among those treated with Bystolic, 7% experienced headaches.

a. Based on the given information, can you conclude that in some cases, Bystolic causes headaches? Why or why not?

b. While 677 subjects were treated with Bystolic, another 205 subjects were given a placebo, and 6% of the placebo group experienced headaches. What does this additional information suggest about headaches as an adverse reaction to the use of Bystolic?

c. Is this clinical trial an observational study or an experiment? Explain.

d. In this clinical trial, what is blinding and why is it important in testing the effects of Bystolic?

e. What is an experimenter effect, and how might this effect be minimized?