Optional Exercise 1: Find the fit of a straight line model in your Hubble diagram. Excel (or another graphing program) can find the fit automatically using a "trendline." The program tries to find a straight line that passes as close to all the data points as possible, then measures how far each point falls from this straight line.
See SkyServer's Graphing and Analyzing Data tutorial to learn how to make a trendline in Excel.
Multiply the Rsquared value by 100 to find the fit as a percentage. What is this number? Is a straight line a good fit to your data?
