I started running a few weeks back and I want to know if I'm improving speed-, distance- and duration-wise. I have a set of data like these (this is bogus data), currently in Excel: 15 13 16 17 15 15 14 17 17 and I want to know if these numbers get larger with time. How would I do that. I calculated the slope with ongoing number on the x-axis and the changing value on the y-axis. If this is a correct way, what does that number actually tell me regarding the grade of improvement? Is there a much better way to do so?