In a lab measuring the charge to mass ratio of an electron I am having trouble with the error analysis. Specifically, this lab measured the radius of a curved path of an electron in a magnetic field (generated by Helmholtz coils with a a current 'I' running through them) with the velocity of the electron due to an accelerating potential in an anode. My question is about the uncertainty in the final answer. Measurements were taken at 5 set radii, for 3 set accelerating potential, and I measured the current in the Helmholtz coils required to reach the 5 radii at the 3 accelerating potential. There was uncertainty in the radii, in the accelerating potential, and in the current through the Helmholtz coils. I solved for the charge to mass ratio of each of these 15 measurements (3 accelerating potential for each of the 5 radii) and I propagated error through each of the 15 measurements using: δ(charge to mass ratio)=(average charge to mass ratio)* √[(δI/I)^2+(δr/r)^2+(δV/V)^2] (I=current through coils, r=radius, V=accelerating potential) My issue is, I have 15 measurements for the Charge to mass ratio and the 15 corresponding uncertainties. How do I use these to express the final value in the lab? Because if I use a standard deviation of the 15 measurements, I'm essentially throwing my 15 calculated uncertainties out the window, am I not? Should I not be averaging the 15 measurements for the charge to mass ratio to begin with? Any insight is helpful as I am clearly at a loss.