Department of Statistics, The Ohio State University
Statistics and Biostatistics Colloquium Series

Interval and ratio scale data present a challenge in logistic regression modeling because they should not be included in their original, continuous, form unless linearity in the logit holds. This talk will discuss three methods for assessing the scale of continuous covariates: quartile dummy variables, lowess plots and fractional polynomials. These methods can help determine whether the variable should be entered "as is" into the model, whether a transformation of the variable should be used, or whether categories should be established and included in the model through the use of dummy variables. Application to real data will be presented and discussed. Meet the speaker in Room 212 Cockins Hall at 4:30 p.m. Refreshments will be served.