I had a question about how to properly perform error analysis on a series of distance measurements. I need to find the relative error in the distance. I was wondering, should I use the instrument uncertainty divided by the measurement (in this case, it would be 0.005m / (mean measurement)). Or, should I be using the formula that relates absolute error to standard deviation: σx=sx/(N1/2), then use this value to find relative error. Or, should I use whichever one is larger to account for the largest possible error?