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Homework Help: How to calculate the average with uncertainties?

  1. Feb 28, 2017 #1
    1. The problem statement, all variables and given/known data
    How to calculate the average given the uncertainties in each measurement 8.70 +/- 0.28, 9.680 +/- 0.046, 9.700 +/- 0.055, 9.720 +/- 0.067?

    2. Relevant equations

    3. The attempt at a solution
    I know I add the values and divide by 4. I also know I add the absolute uncertainties but idk if I divide them by 4. Please help I've gotten 9.45 +/- 0.448 meters
  2. jcsd
  3. Mar 1, 2017 #2


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    Hello Tyler, :welcome:

    In the case off different accuracies, you have to weight the measurements when averaging. The appropriate weight of a measurement is ##1\over \sigma^2##.
    Here, ##\sigma## is the (estimated) inaccuracy
    Last edited: Mar 1, 2017
  4. Mar 1, 2017 #3


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    It's "weight the measurements".
    Well, it's not so much the accuracy as the inaccuracy.
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