The mean weight of a group of boys is 145 lb, with a standard deviation of 4 lb. If the weights are normally distributed, what percent of the boys from the group weigh between 147 and 155 lb? Round your answer to one decimal place. a. 19.1% b. 49.4% c. 68.5% d. 30.3% e. 31.5%

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.