Refer to the Journal of Human Stress study of firefighters, Exercise 12.5. It is thought that a
Question:
Refer to the Journal of Human Stress study of firefighters, Exercise 12.5. It is thought that a complete second-order model, shown here, will be adequate to describe the relationship between emotional distress and years of experience for two groups of firefighters—those exposed to a chemical fire and those unexposed.
E(y) = β0 + β1x1 + β2 x12 + β3x2 + β4x1x2 + β5x12x2
where
a. What hypothesis would you test to determine whether the rate of increase of emotional distress with experience is different for the two groups of firefighters?
b. What hypothesis would you test to determine whether there are differences in mean emotional distress levels that are attributable to exposure group?
c. The second-order model was fit to data collected for a sample of 200 firefighters, resulting in . The reduced model, E(y) = β0 + β1x1 + β2 x12, is fit to the same data, resulting in SSE = 795.23. Is there sufficient evidence to support the claim that the mean emotional distress levels differ for the two groups of firefighters? Use α = .05.
Data from Exercise 12.5
The Journal of Human Stress (Summer 1987) reported on a study of “psychological response of firefighters to a chemical fire.” The researchers used multiple regression to predict emotional distress as a function of the following independent variables. Identify each independent variable as quantitative or qualitative. For qualitative variables, suggest several levels that might be observed. For quantitative variables, give a range of values (levels) for which the variable might be observed.
Step by Step Answer:
Statistics For Engineering And The Sciences
ISBN: 9781498728850
6th Edition
Authors: William M. Mendenhall, Terry L. Sincich