An article in Urban Ecosystems. "Urbanization and Warming of Phoenix (Arizona, USA): Impacts, Feedbacks and Mitigation" (2002, Vol. 6, pp. 183-203), mentions that Phoenix is ideal to study the effects of an urban heat island because it has grown from a population of 300,000 to approximately 3 million over the last 50 years and this is a period with a continuous, de- tailed climate record. The 50-year averages of the mean annual temperatures at eight sites in Phoenix are shown below. Check the assumption of normality in the population with a probabil- ity plot. Construct a 95% confidence interval for the standard deviation over the sites of the mean annual temperatures. Site Sky Harbor Airport Phoenix Greenway Phoenix Encanto Waddell Average Mean Temperature (C) 23.3 21.7 21.6 21.7 Litchfield Laveen Maricopa Harquahala 21.3 20.7 20.9 20.1