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A student's confusion over Student's t-test values

  1. Oct 16, 2005 #1

    I've been working on this assignment for the past while, having to do with independent t-tests and the like. I have two major questions that I can't wrap my head around:

    - When looking at the critical values of Student's t distribution table, what do you use as a critical value if your df value is not listed specifically? Say you need to know the critical value for a df of 120, but it only has the critical values for a df of 100 and a df of 140...
    - On one of the [computer generated] analyses, I keep getting negative values for the t-value (-5.xxxx). I have no clue what this means. How is a negative number significant? Is it an error I've made?
  2. jcsd
  3. Oct 16, 2005 #2


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    - Interpolate between 100 and 140.
    - the numerator for the t value is = (statistic - hypothesis). If statistic < hypothesis then t < 0.
    Last edited: Oct 17, 2005
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