I have the following variables which are expected to influence the dependent variable kg waste:
turnover (continuous), restaurant type (either D or I), operation (either P or N), owner (either M or F).
To analyse the effect of these variables on kg waste I would like to investigate first the collinearity between these variables prior to running a model. However, this is where I run into problems.. pairwise scatterplots do not tell me a lot and when I run this code:
cor.test(df$restauranttype,df$turnover,method="spearman")
I get this error message:
'x' must be a numeric vector
How do I explore collinearity of continuous and categorical independent variables?
What model would you suggest using?