Treats logistic as a function of distance; for a given distance it computes
function at all covariate values in data.
     
    
    Usage
    logisticbyz(x, distance, models, beta)
 
    
    Arguments
- x
- covariate data 
- distance
- single distance value 
- models
- model list 
- beta
- logistic parameters 
 
    
    Value
    vector of probabilities