Drug and life expectancy

Imagine that the drug for severe depression from this week’s Discussion was approved for use in humans. Researchers now want to know whether people using this drug have a different life expectancy than the rest of the general population. A sample of 100 patients who use the drug are followed over time. Those that use the drug have a mean life expectancy of 71.30 years. The mean life expectancy for the general population is 75.62 years. The population standard deviation is 28.