Cholesterol levels for a group of men aged 30-39 follow an approximately normal distribution with mean 193.15 milligrams per deciliter (mg/dl). Medical guidelines state that men with cholesterol levels above 240 mg/dl are considered to have high cholesterol and about 9.1% of men fall into this category. 1. What is the Z-score that corresponds to the top 9.1% (or the 90.9-th percentile) of the standard normal distribution?