15. To test whether the mean time needed to mix a batch of material is the same for machines SELF test Produced by three manufacturers. the Jacobs Chemical Company obtained the following data on the time (in minutes) needed to mix the material. Manufacturer 2 3 20 28 20 26 26 19 24 31 23 22 27 22 a Use these data to test whether the Population mean times for mixing a batch of material differ for the three manufacturers. Use a > .05. b. At the a > .05 level of significance. use Fisher's LSD Procedure to test for the equality of the means for manufacturers 1 and 3. What conclusion can You draw after carrying out this test 16. Refer to exercise 15. Use Fisher's LSD Procedure to develop a 95% confidence interval SELF test estimate of the difference between the means for manufacturer 1 and manufacturer 2. 17. The following data are from an experiment designed to investigate the Perception of cor. Porate ethical values among individuals specializing in marketing (hisher scores indicate higher ethical values). Marketing Managers Marketing Research Advertising AVIAAVIV a Use a > .05 to test for significant differences in Perception among the three Sroups. b. At the a > .05 level of significance. we can conclude that there are differences in the Perceptions for marketing managers, marketing research specialists, and advertising specialists. Use the Procedures in this section to determine where the differences occur. Use a > .05. 18. To test for any significant difference in the number of hours between breakdowns for four machines, the following data were obtained. Machine 1 Machine 2 Machine 3 Machine 4 6.4 8.7 I1.I 9.9 7.8 74 103 12.8 5.3 94 12.1 7.4 10.1 10.3 10.8 8.4 9 2 11.3 73 8.8 11.5