The enlargement of brain ventricles has been proposed as an indicator of Alzheimer’s disease progression. Biomedical engineers have produced software systems which allow the change in size of brain...

The enlargement of brain ventricles has been proposed as an indicator of Alzheimer’s disease progression. Biomedical engineers have produced software systems which allow the change in size of brain ventricles to be accurately measured from 3D magnetic resonance (MR) scans. The file “Alzheimers Data. mat” contains the result of a study in which 18 Alzheimer’ spatients had their disease progression measured using two methods, a “task-based” method and ventricle size. Each patient was measured at two time points, and the file “Alzheimers Data. mat” shows the change in the “task-based” method (first column, positive values show symptoms becoming worse) and the change in ventricle size (second column, in cm3). Investigate how strongly these measures are correlated as follows:

2. Calculate the Pearson’s correlation coefficient between the values of the two methods. What does this mean?