The amount of pollutants that are found in waterways near large cities is normally distributed with mean 9.1 ppm and standard deviation 1.3 ppm. 7 randomly selected large cities are studied. Round all answers to 4 decimal places where possible. What is the distribution of ¯xx¯? ¯xx¯ ~ N(Correct,) Find the IQR for the average of 7 cities. Q1 =  ppm Q3 =  ppm IQR:  ppm

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.