Hi all, I am trying to use excel to do error analysis. I have a set of data points, and I have the average value and standard deviation of all the data points (which I use to plot the error bars). I want to use the excel to plot the best fit line and extreme line to get the error. However, it seems that excel does not allow me to draw extreme lines :( Therefore, I was wondering if there is a way for me to calculate out the error, if I am given the standard deviation of all the datapoints and the equation of the best-fit line. The value I want is the gradient of the graph with its associated error. Does anyone know how to draw extreme lines in excel? If not, can someone tell me how I can calculate the error of the gradient? Thanks!