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K^2
#4
Dec3-12, 02:53 AM
Sci Advisor
P: 2,470
Measuring the Speed of Light (Foucault Method)

Quote Quote by ltetor View Post
The mean speed of light calculated from this experiment was (2.9972 0.0139) x 108 m/s.
If that is your estimate of the error, how do you explains statistical error being (2.9972 0.1071) x 108 m/s?

You should always check the statistical error on your data. It should never be higher than the error you claim. You have made a mistake somewhere by a whole order of magnitude. It doesn't affect your answer, but it affects how believable your answer is. If you claim an error of less than 0.5%, you need to show statistical variation of less than 0.5%. It's not. The fact that you didn't get 3.1 for an answer is entirely down to luck. Unless it's not even that. Did you keep all of the data points you took, or only the ten you liked?


Just to illustrate this a little better I've attached a plot of your data. Red dots are the data from the table. Pale blue band is the probability distribution according to 2.9972 0.0139 you claim, with solid blue dashes marking off the area of the band that should contain 90% of your data points according to that error. Doesn't look good, for your claim, does it?
Attached Thumbnails
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