D. In each of the following situations, a random sample must be obtained. Determine whether a cluster, stratified, or systematic random sampling would be appropriate. Explain in detail how the sampling is to be conducted. Do not discuss expected results or conclusions. 1. A large convenience store chain wishes to determine its customers' level of satisfaction with regard to their service. 2. A nationwide survey on charter change is to be conducted. (Note: there are seventeen regions in the Philippines.) 3. An educational researcher wants to compare the difference in career goals between male and female students of Otto Hahn University who has 10,000 students. 4. A social researcher wants to determine whether electronic engineers who work in the communications field earn more than those who are in semiconductor industries. 5. A market analyst would like to compare the durability, in terms of mean time before wear, of two leading brands of car tires. E. The numbers of incorrect answers on a true or false competency test for a random sample of 15 students were recorded as follows: 2, 1, 3, 0, 1, 3, 6, 0, 3, 3, 5, 2, 1, 4, and 2. Find a. mean, b. median, c. mode, d. range, e. standard deviation, f. variance F. A corporation administers an aptitude test to all new sales representatives. Management is interested in the extent to which this test is able to predict their eventual success. The accompanying table records average weekly sales (in thousands of pesos) and aptitude test scores for a random sample of eight representatives. Test 55 60 85 75 80 85 65 60 Scores Weekly 10 12 28 24 18 16 15 12 Sales 1. Plot a scatter diagram 2. Estimate the linear regression of weekly sales on aptitude test scores. 3. Estimate the weekly sales when test scores is 70 4. Determine the coefficient of determination