Suppose that the amount of time that students spend studying in the library in one sitting is normally distributed with mean 48 minutes and standard deviation 19 minutes. A researcher observed 9 students who entered the library to study. Round all answers to 4 decimal places where possible.  is the assumption of normal necessary? YesNo The top 15% of the total study time for groups of 9 students will be given a sticker that says "Great dedication". What is the least total time that a group can study and still receive a sticker? minutes

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.