Logistic reg

Question 1

binary logistic regression

Answer 1

Especially in medical and biomedical studies, the dependent variable is a dichotomous (binary) categorical variable.
o Randomized trials with outcome as dead or alive
o Cohort studies with outcome as disease no disease
o Case/control studies with subjects classified as disease or no disease

Question 2

requirements for binary logistic regression

Answer 2

o 1)An outcome variable with two possible categorical outcomes (1=success; 0=failure).
o 2)A way to estimate the probability P of the outcome variable.
o 3)A way of linking the outcome variable to the explanatory variables.
o 4)A way of estimating the coefficients of the regression equation, as well as their confidence intervals.
o 5)A way to test the goodness of fit of the regression model.

Question 3

How to interpret regression Exp(B)

Answer 3

subtract 1 from this value and get the percent increase (or decrease) in the odds caused by that variable
a year increase in age increases the odds of cancer by 0.8% (exp b is 1.008)