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Uncertainty and averages.

  • #1

Homework Statement


In my lab we are doing Franck Hurtz experiment with heated mercury and electron beams. We already took data but i need a little help. I have the locations of the minimums A B C D and E, and each point has it's own uncertainty. a b c d and e. What i needed to find was the difference between each min and the next, so A-B, B-C... and then find the average of each these differences. I don't know how to do the uncertainty for my calculations.


Homework Equations


My actual values are
1.4
1.94
2.43
2.98
3.66
With uncertanities (in order)
0.003686
0.008077
0.002263
0.009459
0.003834


The Attempt at a Solution

 

Answers and Replies

  • #2
CompuChip
Science Advisor
Homework Helper
4,302
47
I would say that the most general rule is the "sum of squares" rule,
[tex](\Delta d)^2 = (\Delta x)^2 + (\Delta y)^2[/tex]
where d = x - y is the difference of two independent quantities x and y.

However, I think that
[tex](\Delta d) = (\Delta x) + (\Delta y)[/tex]
is also commonly used, giving the "rough" estimate that the deviation from the mean is at most the sum of the two maximal deviations.
 

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