# percent deviation for linear regression

I have 2 sets of experimental data to which I applied a linear fit using Matlab. I can use the slope value to compare between both of them.

My question is: can I use the following percent deviation equation for the linear fit to compare between these 2 sets?

$$\%\text{ deviation} = \frac{\text{last point - first point}}{\text{last point}}\times 100$$

The first point of the linear fitting when (x=0), the last point where my data end (x=311 in this example)

In this example the slope is -0.01569 and the %deviation is -4.063%