Understanding N-1 in the Sample Variance Formula

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  • Опубліковано 18 лис 2024

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  • @_P_a_o_l_o_
    @_P_a_o_l_o_ 8 місяців тому +4

    I really loved the first argument! Having n-1 at the denominator to have 0/0 when n=1 is such a neat way to mathematically express that from one sample cannot infer anything on the variance!

    • @ron-math
      @ron-math  8 місяців тому +2

      It is also my favorite argument. I also call it the "interviewee's argument". You can use it in an interview if you are asked to explain this to someone who doesn't know much statistics.

  • @pedroalonso7606
    @pedroalonso7606 8 місяців тому +3

    My favourite argument is the last one, because it was new to me.

    • @ron-math
      @ron-math  8 місяців тому +1

      It is also the standard one in a mathematical statistics course.

  • @ron-math
    @ron-math  8 місяців тому

    Which is your favorite argument and which one did you learn in school?

  • @zirconpetrichor5519
    @zirconpetrichor5519 8 місяців тому +1

    Regarding the compensation argument, doesn't the sample mean minimize the sample variance (understood as a function of the parameter which would take the sample mean's place) regardless of the denominator? If I were to argue the n-1 denominator based solely on this argument I think I could argue for a n-2 denominator and so on...

    • @ron-math
      @ron-math  8 місяців тому

      Exactly. It only says a compensation is needed, but doesn't say how much.
      So these 4 arguments are ordered in the level of "precise".