7. (11 points) A new bottling machine is being tested by a company. During a test run, the machine lls 24 cases, each containing 12 bottles. The company wishes to estimate the average number of ounces of ll per bottle. Six cases are selected via a SRS, with four bottles selected via a SRS from each. The data are shown in the table: Average ounces Case of ll for sample Sample variance 1 7.9 0.15 2 8.0 0.12 3 7.8 0.09 4 7.9 0.11 5 8.1 0.10 6 7.9 0.12 (a) 3 points) Estimate the average number of ounces per bottle. (b) (3 points) Estimate the stande error of the estimator of the average. (c) 5 points) Redo (b) and (c) using ratio estimation assuming M0 is unknown. Compare the results with those in (b) and (c), and comment on your ndings