arcgis desktop - Correlation between point feature (disease) and elevation

I have a problem! How can I calculate the correlation between point feature and Dem raster?

Hypothesis: disease prevalence in high altitude is more than low altitude. I must do this in ArcGIS 10 and classify the altitude to 15 or 20 classes.

For example 0-200 meter above sea-level, 200-400 m and ... . I will join these altitude classes with disease prevalence shapefiles and then calculate the correlation between two entities. When I look at the layers, I see the correlation between altitude and disease.