Larry Hoover wrote:
>> Tea, coffee, and cola drinks are very different than each other. Teasing out
> which is better or worse has yet to be done. The variability in the caffeine
> consumption has nothing to do with the type of drink. It just happens to be
> the variable they measured. You can be sure people will want to know if
> there are other confounding variables being coincidentally measured in this
> study. Stay tuned.
>
Well my thought was that (assuming they got their data by asking
subjects about their daily habits) caffeine was not actually the
variable being measured, but merely the one they chose to report. It
seems likely coffee (and possibly also tea, cola and other caffeine
containing consumables) intake was estimated by the subjects, and
caffeine intake further estimated from that (adding additional
uncertainty due to quite significant variation in caffeine content in
coffee by preparation method, roast, beans used, etc). So unless I'm
wrong about how they gathered their data, their data about
caffeine-intake is one estimate further away from actual measurement
than their data about about coffee / tea / etc intake.
Eric
