I did a study measuring the relationship between metamemory and actual memory scores in a test. Basically what I find is that only those people who are good or bad in memory have a accurate metamemory. However, those in the middle of the distrution do not. I have analysed my results with simple correlations (weak but reliable correlation when all the sample is included) and dividing the sample in four groups according to their scores in the objective memory test. Is there any way to analyze the data in a different way?