Hi all, I'm hoping someone can help me out with this problem. I am following an example of a previous report to analyse some test results, but am having trouble with this step. The tests plot moment-rotation curves of a horizontal member fixed into a vertical member. You run 5 tests, and for each test, fit a polynomial curve to the results. Then, it seems, you produce a single 'mean' curve and use this to derive the stiffness of the joint in rotation. The problem i have is that using the results in the previous report, I cannot get an 'average' which matches that listed in the report. On the attached excel I have listed out the co-efficients for 2 lots of 5 tests, and showed the co-effecients which are listed in the report as the average. You'll see that I can't get them to match! i've tried mean, absolute and reciprocal averages all to no luck. The fact that a constant (x0) appears in the 'average' equation makes me thing i'm misunderstanding something. Also on the excel is a plot from one test which might help to illustrate. Sorry if i've waffled, I just want to make sure i've explained properly! Any pointers would be greatly appreciated.