Refer to the Journal of Engineering for Gas Turbines and Power (Jan. 2005) study of gas turbines augmented with high-pressure inlet fogging, Exercise 15.14. The Kruskal–Wallis test was used to compare the heat rate distributions for traditional, advanced, and aero derivative gas turbine engines. A MINITAB printout of the analysis is shown above. 

a. Give the null and alternative hypotheses tested.

b. Find the critical value of X² used in the rejection region of the test at α = .01.

c. Locate the test statistic on the MINITAB printout and make the appropriate conclusion.

d. Interpret the p-value of the test shown at the bottom of the printout.

Data from Exercise 15.14

Refer to the Journal of Engineering for Gas Turbines and Power (Jan. 2005) study of gas turbines augmented with high-pressure inlet fogging, Exercise 8.29. The data on engine heat rate (kilojoules per kilowatt per hour) is saved in the GASTURBINE file. Recall that the researchers classified gas turbines into three categories: traditional, advanced, and aero derivative. Suppose you want to compare the heat rate distributions for traditional and aero derivative turbine engines.

Data from Exercise 8.29

During periods of high electricity demand, especially during the hot summer months, the power output from a gas turbine engine can drop dramatically. One way to counter this drop in power is by cooling the inlet air to the gas turbine. An increasingly popular cooling method uses high-pressure inlet fogging. The performance of a sample of 67 gas turbines augmented with high-pressure inlet fogging was investigated in the Journal of Engineering for Gas Turbines and Power (Jan. 2005). One measure of performance is heat rate (kilojoules per kilowatt per hour). Heat rates for the 67 gas turbines are listed in the table on the bottom of page. Suppose that a standard gas turbine has, on average, a heat rate of 10,000 kJ/kWh. Conduct a test to determine if the mean heat rate of gas turbines augmented with high-pressure inlet fogging exceeds 10,000 kJ/kWh. Use α = .05.

Transcribed Image Text:

Kruskal-Wallis Test on HEATRATE ENGINE Median ive Rank Advanced 21 9669 15.0 -5.39 Aeroderiv 7 12414 44.1 1.46 Traditional 39 11183 42.4 4.17 Overall 67 34.0 P = 0.000 P = 0.000 H = 29.13 DF = 2 H = 29.13 DF = 2 (adjusted for ties)