A researcher wants to estimate the mean blood cholesterol level of young men ages 15-25 with a 90.15% confidence interval. The blood cholesterol level of young men follows a Normal distribution with standard deviation σσ = 45 mg/dl. How large a sample would the researcher need to take to estimate the mean blood cholesterol to within 5 mg/dl? A sample of at least ________ people.

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.