1. A grocery store manager would like to have an idea concerning the average amount milk the store sells per day. In a sample of 56 days, the average amount number of gallons sold was 117 with a standard deviation of 20 gallons. What is the lower bound of the 95% confidence interval? (please express your answer using 2 decimal places)

2. In an effort to reduce energy costs, a major university has installed more efficient lights as well as automatic sensors that turn the lights off when no movement is present in a room. Historically, the cost of lighting an average classroom for 1 week has been $265. To determine whether the changes have signficantly reduced costs, the university takes a sample of 84 classrooms. They find that the average cost for 1 week is $244 with a standard deviation of $63. When testing the hypothesis (at the 5% level of significance) that the average energy use has decreased from the past, what is the test statistic? (please round your answer to 2 decimal places) 3. Historically, the proportion of students entering a university who finished in 4 years or less was 60%. To test whether this proportion has decreased, 114 students were examined and 50% had finished in 4 years or less. To determine whether the proportion of students who finish in 4 year or less has statistically significantly decreased (at the 10% level of signficance), what is the critical value? (please round your answer to 2 decimal places)

4. In an effort to reduce energy costs, a major university has installed more efficient lights as well as automatic sensors that turn the lights off when no movement is present in a room. Historically, the cost of lighting an average classroom for 1 week has been $265. To determine whether the changes have signficantly reduced costs, the university takes a sample of 50 classrooms. They find that the average cost for 1 week is $247 with a standard deviation of $60. When testing the hypothesis (at the 5% level of significance) that the average energy use has decreased from the past, the null and alternative hypotheses would be which of the following?

5. Suppose the returns of a particular group of mutual funds are normally distributed with a mean of 12% and a standard deviation of 5.2%. If the manager of a particular fund wants to be sure that his fund is NOT in the bottom 10% of funds with the lowest return, what return must his fund have? (please round your answer to 2 decimal places)