The literature on Survival Analysis is mainly from the Medical science where tipically the researcher want to evaluate the effect of a treatment to that of another one. So far, all the example I read and studied thus contain one or more categorical variable (with at least 2 levels) and possibly some continuous variable as a covariate. Anyway the main interest is on a categorical variable (e.g. treatment).
Is it possible and correct to run a non parametric Cox model (or alternatively a parametric one) using only one or more continuous variables? In particular without categorizing the continuous var into 2 or more groups?
Something like a logistic regression.
To give you a more practical example, I'm trying to model the survival of say bush in a field depending on the number of cows in the same field.
I'm pretty sure it can be done but the lack of examples leave me in the doubt.
If possible how can one use the predict function for example to predict the survival when the predictor has a specified value? like survival of my plant when 10 cows are in the field...
any help is welcome!