I have two sets of acceleration data in terms of time. In one set the acceleration increases more linearily than another set. How can I show the linearity difference of the two set of data best? Should I use Pearson Correlation or Linear Regression? If I get r = 0.8 and 0.98 by Pearson Correlation, how I can interpretate the result? Do they have very big difference on the linearity based on 0.8 and 0.98?