I have obtained a value for the background illumination with an associated error which was kept constant during a double slit experiment. Also, I have acquired a value for the average noise/fluctuations of the measured voltage values.
Now I want to plot the intensity distribution. Can I just subtract the background illumination (treating it as an offset)? Furthermore, do I have to calculate the resulting error using the error propagation formula for adding two measurements for every point on the intensity distribution graph?
In addition, do I have to simply add the noise to each of the errors?