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Homework Help: Simple average question using sig figs within ± 0.0 of uncertainty?

  1. Jan 20, 2012 #1
    Simple average question using sig figs within ± 0.0 ?

    1. The problem statement, all variables and given/known data

    Consider the following measurements of mileages:
    23.8 mph, 20.1 mph, 26.5 mph, 20.7 mph, 21.7 mph, 27.6 mph,
    30 mph, 28 mph, 27.4 mph, 34.3 mph, 26.5 mph, 32.7 mph.
    What is the average mileage (using sig figs)?

    Answer in units of mph Your answer must be within ± 0.0 mph.

    2. Relevant equations

    Avg=Total Sum/number of variables

    3. The attempt at a solution

    The average calculated was 26.60833333. And Since two variables have only two sig figs, I thought the answer should be 27. But it was a wrong answer.
    But the last part of question asked the answer to be within ± 0.0 mph.

    What does 'within ± 0.0 mph' means? No uncertainty? Or typo of 0.1 or 0.01?
    What should be the correct answer?
    Last edited: Jan 20, 2012
  2. jcsd
  3. Jan 20, 2012 #2

    I like Serena

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    Homework Helper

    Welcome to PF, bobi! :smile:

    'within ± 0.0 mph' means within ± 0.05 mph.
    That is, with 1 digit after the decimal point.
    So your average would be 26.6 ± 0.0 mph
  4. Jan 20, 2012 #3
    Thanks a lot!!
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