That's not actually true. In fact, practically every scientific survey that has ever been done does not have a truly random sample. Yes, of course there's a risk of error -- but given the large number of instruments in the register, and no obvious reasons for large biases (i.e., the kind that would cause JG instruments to be only 50% as likely to appear in the Register as FG instruments), the chance that the proportions in the Registry are way off is likely to be extremely low. Nothing is absolute in the survey world, but you learn to be pretty comfortable with things that you're 95-99% (or more) sure of. In this case, I'd be pretty confident that the order of popularity of the finishes -- FG, JG, then MG -- is probably right, as well as the general proportions. I would not be remotely confident about the relative proportions of the rarer finishes because there's a good reason to believe the registry is biased towards including them.dpowell wrote:In a real scientific survey, they would be randomly chosen. I'm just saying that anyone who extrapolates production totals from the data without knowing the effects of those variables is at risk of error. YMMV.FretlessOnly wrote: Well, I'm a scientist too (and I use statistics regularly), and I don't see how one can claim that the members aren't randomly "chosen." In fact, they are not chosen at all (which to me is irrelevant to this point); it is a voluntary thing that depends upon two factors:
1. interest in a particular brand; and
2. access to the internet.
Neither of these two population characteristics would seem to me to favor a particular finish, and further, neither would seem to favor a proclivity toward registering or not registering an instrument here. If anything, actually choosing a sample from the RIC population at large would be more likely to produce skew than would the voluntary joining of this website and registering one's instrument(s). To me, anyway.
I would agree that the members here who have registered their instruments may have a greater liklihood to own more rare finishes such as desert gold, azureglo, blue boy, teal, etc., but as to the big three, I think that our registry sample on these must be fairly representative of the population as a whole.
Just because you don't know all of the variables doesn't make you can't make a very educated and likely rather accurate guess, especially if you've thought through possible sources of bias.
