AP Statistics Quiz 2.2 Name: 1. A fire department in a rural county reports that its response time to fires is approximately Normally distributed with a mean of 22 minutes and a standard deviation of 3.9 minutes. (a) Make an accurate sketch of the distribution of response time. (b) Use the empirical rule to find the proportion of response times between 14.2 and 29.8 minutes. (c) Calculate and interpret the 80th percentile of the distribution of response times. ****make a statement interpreting your result**** (d) The national mean response time is 18.5 minutes. What proportion of all response times for this fire department are below the national mean response time? ****include in your answer a statement interpreting your result in the context of the problem** *2. The amount of sleep that elementary school children get per night follows a Normal distribution with a mean of 9.5 hours and a standard deviation of 0.55 hours. (a) Find the proportion of elementary school children who get between 9 and 10 hours of sleep per night. Sketch the Normal curve and shade the area under the curve that is the answer to the question. *include in your answer a statement interpreting your result in the context of the problem** * (b) Is it unusual for an elementary school student to get at least 12 hours of sleep? Justify your answer. 3. Find the proportion of observations in a standard Normal distribution that satisfies each of the following statements . a. z 2.13