To complete this Application Assignment, answer the following problems:
Problem 10.1: Researchers used multiple linear regression to test the relationship between FEV (forced expiratory volume) and sex. Next they retested the relationship between FEV and sex after adding the variable age. Open the following to see the SPSS output:
Week 10 First Problem Output
Interpret the results by answering the following questions:
1.Was the relationship between sex and FEV significant?
2.What percentage of the variability of FEV was explained by sex? (Use the coefficient of determination.)
3.Was the relationship of age and FEV significant?
4.Was age a confounder of the relationship between sex and FEV?
5.What percentage of the variability of FEV was explained by sex and age? (use coefficient of determination)
Problem 10.2:
A case-control study was conducted on patients undergoing extensive cardiac surgery. Cases were given pre-operative medication (study medication) to increase their chance of survival. The outcome of interest is "alive discharge from the hospital" (survival). The relationship between assignment as a case or a control, and survival is tested using logistic regression. See the document below for this output (Second Problem Output, first part).
Then, the relationship between assignment as a case or a control, and survival is tested again, this time adjusting for the presence of sepsis (a whole body response to infection) after surgery using multiple logistic regression. See the document below for this output (Second Problem Output, second part):
Week 10 Second Problem Output
Interpret the results by answering the following questions:
1.Was the relationship between case/control and survival significant?
2.Was the relationship of sepsis and survival significant?
3.Was sepsis a confounder of the relationship between case/control and survival?
4.What would the researchers have concluded about the study medication if they had ignored the effect of sepsis on survival in their analysis?
Copy and paste (or use the File/Export option in SPSS) any required data charts or summaries into a Word document, or export the data output as a Word/RTF document.