> "harry" <harald.vanlintelButNotT...@epfl.ch> wrote in message
> news:4837e477$1_5@news.bluewin.ch...
> |
> | "Tom Roberts" <tjroberts...@sbcglobal.net> wrote in message
> | news:99BZj.108$uE5.87@flpi144.ffdc.sbc.com...
> | > Jerry wrote:
> | [...]
> | > Imagine that one selected a different group of ten men. The average
> for
> | > this second group is almost surely not 162 lbs. Consider a third,
> fourth,
> | > fifth,... group of ten men, and plot the distriution of the averages
> for
> | > the different groups. The AVERAGES will display a variance, and that
> | > variance is related to the variance of the weights of the individual
> men.
> | > THIS is what statistics does: it tells you what the variance of the
> | > average will be, given the variance of the individual measurements
> (here
> | > mens' weights).
> | >
> | > For the case (like Miller's) where you have only one group of ten men
> to
> | > consider, honesty precludes one from claiming the average is 162 +-
> 0.5,
> | > and one must claim 162 +- sigma, where sigma is determined from the
> | > distribution of the ten mens' weights. In the language of statistics,
> the
> | > mean of those ten mens' weights is the best unbiased predictor of the
> true
> | > average, and the sigma is the best unbiased predictor of how
> accurately
> | > the average of those ten weights reflects the true average. Note these
> are
> | > "predictors", because one does not know the true values, one only
> knows
> | > the ten values one measured.
> | >
> | > To learn how to compute that sigma you need to STUDY. If
> | > those ten men's weights are randomly but uniformly
> | > distributed between 131 and 245 lbs, the sigma (errorbar
> | > on the average) will be about 10 lbs, not 0.5 lbs.
> | >
> | > That's PRECISELY what I did for each run of Miller's data: For each of
> his
> | > eight orientations he averaged 40 data points. I computed the variance
> of
> | > those eight averages from the variance of the 40 points that went into
> | > computing each one. Those variances (errorbars) GREATLY exceed the
> | > variation among the eight averages, showing that the variation Miller
> used
> | > to make his result is not significant. This, in turn, makes any
> conclusion
> | > based on his results be insignificant: Miller concluded the average is
> 11
> | > km/s, but the errorbar on that average is something like 100 km/s;
> Miller
> | > determined an average direction, but the errorbar on that direction
> | > includes all possible directions.
> |
> | Well explained this time! :-)
> |
> | Harald
> Consider why did Einstein say
> the speed of light from A to B is c-v,
> the speed of light from B to A is c+v,
> the "time" each way is the same,