Question

12 to 15

that of the general population of males at State? For Homework 12. A marine biologist has evidence from other as evidence from other studies that the number of fish is declining in certain lakes because of pollution. The biolo- gist decides to compare the fish population of these lakes to the number of fish in the popu- lation of lakes of comparable size. A sample of 16 lakes has a mean of 62,000 fish with a standard deviation of 12,000. The population mean is 66,000. Using an alpha level of .05, list the (a) hypotheses, (b) df, (e) critical value of t, (d) decision rules, (e) computation, and (f) in- terpretation of the test. 13. A researcher wants to determine whether a sample mean of 91 with a standard deviation of 33 from a sample of 25 subjects is significantly different from a population mean of 78.2. De- termine (a) lobs (b) df, (e) terit, and (d) whether the sample is from the original population (a = .05). 14. What effect will the following changes have on the power of a statistical test? a. Changing the a level from .05 to .01. b. Using a sample of 40 instead of 30. c. Using a statistical test that makes more spe- cific assumptions about the population pa- rameters. 15. A company that makes processors for comput- ers uses a .05 significance level to reject any lot of processors that does not run at an average of 500 Millions of Instructions Per Second (MIPS). Twenty processors are selected at ran- dom to test the quality of six lots. Below are listed the resulting mean number of MIPS for each of the six lots of processors. Which lots should be rejected as having failed to meet quality standards? Specify the crie you will use for the tests as well as the tobs for each lot. Lot A: X = 502, s = 3.1 Lot B: X = 501.6, s = 3.3 Lot C: X = 499.6, s = 1.3 Lot D: X = 498.3, s = 2.6 Lot E: X = 501.4, s = 3.2 Lot F: X = 500.3, s = .6

Answer 1

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