a. A sports reporter asks 100 baseball fans if Barry Bonds’s 756th homerun ball should be marked with an asterisk when sent to the Baseball Hall of Fame. b. Contrast the three major types of...

a. A sports reporter asks 100 baseball fans if Barry Bonds’s 756th homerun ball should be marked with an asterisk when sent to the Baseball Hall of Fame.

b. Contrast the three major types of observational studies in terms of the time frame when the data are collected.

c. Compare and contrast observational studies and designed experiments. Which study allows a researcher to claim causality?

d. Explain why it is important to use a control group and blinding in an experiment.