In the helicopter transport dataset, we collected variables fatal (yes or no), sev (severe or not severe), htt (helicopter or not helicopter transport).3 other variables were collected:

Driver's sex, day or night, rain or dry.

Male was coded as 1=male, 0=female.

Day was coded as 1=day, 0=night.

Rain was coded as 1=rain, 0=no rain.

MODEL 1 Standard Wald Parameter DF Estimate Error Chi-Square et> ChiSa Intercept 1 -1.1727 0.0710 273.0540 <.0001 but odds ratio estimates point wald effect estimate confidence limits model standard parameter df error chi-square et> Cbisa Intercept 1 -1.4092 0.0759 344.7033 <.0001 sex odds ratio estimates point wald effect estimate confidence limits model standard parameter df error chi-square et> ChiSa Intercept 1 -1.4494 0.1865 60.4042 <.0001 but male day rain odds ratio estimates point wald effect estimate confidence limits sex model regression models selected by score criterion number of variables chi-square included in btt nnp sey>