The serum cholesterol level X in 14-year-old boys has approximately a normal distribution with mean 170 and standard deviation 30. Find the probability that the serum cholesterol level of a randomly chosen 14-year-old boy exceeds 230.

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.