I have done a, but cannot seem to figure out letter b, some help would be apprec
ID: 3315504 • Letter: I
Question
I have done a, but cannot seem to figure out letter b, some help would be appreciated!
The common brushtail possum of the Australia region is a bit cuter than its distant cousin, the American opossum. We consider 104 brushtail possums from two regions in Australia, where the possums may be considered a random sample from the population. The first region is Victoria, which is in the eastern half of Australia and traverses the southern coast. The second region consists of New South Wales and Queensland, which make up eastern and northeastern Australia. We use logistic regression to differentiate between possums in these two regions. The outcome variable, called population, takes value 1 when a possum is from Victoria and 0 when it is from New South Wales or Queensland. A logistic regression model was proposed for classifying common brushtail possums into their two regions using four predictors: sex male (an indicator for a possum being male), skull width, total length, and tail length Estimate 3.35 1.4207 -0.2787 0.5687 1.8057 SE 9.9053 0.6457 0.1226 0.1322 0.3599 3.38 -2.2 2.27 4.3 5.02 Pr( IZ) 0.0007 0.0278 0.0231 0 0 (Intercept) tota tail length (a) Write out the form of the model. (b) Calculate the Odds Ratio for each predictor.Explanation / Answer
Result:
a).
The logistic regression model is
Log(P/(1-P)) =3.35-1.4207*sexmale-0.2787*skullwidth+0.5687*totallength-1.8057*talllength
b).
odds ratio for sex male = exp(-1.4207) =0.2415
odds ratio for skull width = exp(-0.2787)=0.7568
odds ratio for total length = exp(0.5687)=1.7660
odds ratio for tail length= exp(-1.8057)=0.1644