Fig. 2 --- A plot of the standard deviation measured for the data points in each light curve vs. the mean magnitude of the light curve for the KPNO 0.9-m telescope data. Most stars (ie. non-variables) cluster along a line that traces out an empirical estimate for the photometric precision as a function of magnitude. This photometric precision matches that calculated based on a proper treatment for all sources of noise over the full magnitude range.