What is the best way of correlating 2 ratios?
I am postulating that low carotid bifurcations have a longer length of disease beyond the bifurcation, and have measured and created 2 ratios (a bifurcation ratio -length from clavicle to bifurcation divided by total carotid length; and a disease ratio (length from bifurcation to end of disease divided by length from clavicle to end of disease). Is it valid to use simple linear regression/correlation with bifurcation ratio as the independent variable and disease ratio as the dependent variable? A: Ratio measurement scales possess all properties of interval scales plus an absolute zero point. You might want to look at limits of agreement rather than correlation.
