PH140 Biostatistics

PH140 Biostatistics Johns Hopkins University USA

1. Suppose you fit a logistic regression model in which the response variable was whether an individual reenlists and one of the covariates was whether the individual is married. (Y = 1, if reenlists, Y=0, if not; X=1 if married, X=0 if not married) 

Suppose further that the Odds Ratio for the Marriage covariate is 3.04. Explain what this tells us about the relationship between marriage and reenlistment. 

2. How are the residuals for a logistic regression model distributed? (CHOOSE ONE) 

• A. Uniform • B. Normal • C. Exponential • D. Binomial 

(Survival Analysis) 

3. Explain, in words, the meaning of the Survival Function. 

4. Explain, in words, the meaning of the Hazard Function. 

In other words, what is h(t)? 

5. Kaplan-Meier developed a technique to estimate an empirical Survival Function. 

True 

False 

6. The military tends to know a great deal about all of its members. Each service maintains enormous databases that contain hundreds of pieces of information about all its members, to include many past members. 

Describe a plausible situation in which a manpower analyst is confronted with right-censored data.