A cardiologist in Munster, Indiana, has been accused of conducting unnecessary heart surgeries (Cresswell, 2015). Investigators found that the rates for one heart procedure were in the top 10% in the country for the city where this doctor worked. Lawyers countered that there were older and sicker people in this part of the country; yet other afflictions of the elderly—for example, treatment for hip fractures—were no higher in this region. In your own words, explain how the z distribution might play a role in determining whether this cardiologist was conducting unnecessary surgeries.