1) U.S. residential electric bills were expected to decrease slightly during the summer months of 2013, compared with 2012. This was partly due to decreased demand and weather patterns. Electric bills vary by region, and the mean residential bill for July 2013 in the Pacific region was estimated to be $279.36 A random sample of 12 homes in Oregon were selected and the electric bill for July 2013 was obtained for each. The summary statistics were x = $305.72 and s = $40.05. Is there any evidence to suggest that the true mean July residential electric bill in the Pacific region is greater than $279.36 ? Assume the underlying distribution is normal. Use the critical value method at = 0.05.

2. Most water parks use a recycling system so that the only water loss is due to evaporation and splashing. Despite a sophisticated recycling system, the Schlitterbahn Waterpark in New Braunfels, Texas, has informed the city water department of their need for 250,000 gallons of water per day. The city water department selected a random sample of 21 days, and the park's water usage (in thousands of gallons) on each day. The sample produced the following data; x = 245.2 and s = 40.8. Is there evidence to suggest that the mean water usage is different from 250,000 gallons? Use = 0.01 and assume the underlying population is normal.