Cooling method for gas turbines. Refer to the Journal of Engineering for Gas Turbines and Power (January 2005) study of a high pressure inlet fogging method for a gas turbine engine. Recall that the heat rate (kilojoules per kilowatt per hour) was measured for each in a sample of 67 gas turbines augmented with high pressure inlet fogging. In addition, several other variables were measured, including cycle speed (revolutions per minute), inlet temperature (?C), exhaust gas temperature (?C), cycle pressure ratio, and air mass flow rate (kilograms per second). The data are saved in the GASTURBINE file. (The first and last five observations are listed in the table.)
(a) Write a first-order model for heat rate (y) as a function of speed, inlet temperature, exhaust temperature, cycle pressure ratio, and air flow rate.
(b) Fit the model to the data using the method of least squares.
(c) Give practical interpretations of the β estimates.
(d) Find the model standard deviation, s, and interpret its value.
(e) Find the adjusted-R2 value and interpret it.
(f) Is the overall model statistically useful at predicting heat rate (y)? Test using α = .01.