A medical study was looking into the question if using a drug to reduce blood cholesterol level will decrease the risk of a hear
t attack. Middle age men were randomly assigned to two groups. One group of 2051 men took a drug that reduces cholesterol level, and the second group (control) of 2030 men took a placebo. During the next five years, 56 men from the treatment group and 84 men from the control group had heart attacks. Required:
Was the drug treatment effective?
