We occasionally get feedback from our readers. Often, the feedback is positive, letting us know that they find reading these columns interesting, enjoyable, and most importantly, useful. Getting responses like that also makes writing these columns interesting and enjoyable, and makes us feel useful, too. Occasionally, one or more readers finds an error (horrors!) that requires a correction (more horrors!), or presents an alternative approach to, or interpretation of, our discussion. When we wrote out 14-part column on the analysis of noise in spectroscopy, a few readers wrote in, letting us know that they felt that some parts of the derivations were weak, and perhaps less than perfectly rigorous. We took their comments to heart and here present the first of a two-part discussion incorporating the comments. This could be considered a (hide your eyes!) correction, or perhaps, simply another approach to analyzing the situation.
