The daily water consumption during the summer in the city of Chicago has historically been on average of 1.2 million gallons per day with a standard deviation of .6 million gallons per day.
a.) The city starts a water conservation campaign. A random sample of 30 days is selected and the water consumption is recorded. The water consumption is 1.0 million gallons per day. Draw a 99 percent confidence interval around this average. Does the old population average fall in this interval?
b.) Test the hypothesis that the water conservation program reduces water consumption with a 1 percent chance of type 1 error. Compare these results to the confidence interval.