Standard Deviation

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  • เผยแพร่เมื่อ 4 ก.พ. 2025

ความคิดเห็น • 18

  • @vickypalumbo2354
    @vickypalumbo2354 9 ปีที่แล้ว +3

    I can't express how grateful I am for your videos, I just watched your video on Standard Errors and 95% Confidence Limits and this one! They have been extremely helpful, I have my ISA tomorrow and I think I understand the statistics tests now, so thank you:)

    • @joey7415
      @joey7415 4 ปีที่แล้ว

      where are these ? i cant find them

  • @shabnumrashid5240
    @shabnumrashid5240 9 ปีที่แล้ว +4

    hi sir how do we know which formula to apply to which question like the one just n or n-1

  • @marsgrrrl
    @marsgrrrl 2 ปีที่แล้ว

    Thanks Mr Pollock. Here for A-Level Psychology purposes!

  • @JayPatel-mj9wh
    @JayPatel-mj9wh 9 ปีที่แล้ว +3

    Very helpful video, thank you very much!

  • @ruqayyahamin6849
    @ruqayyahamin6849 8 ปีที่แล้ว +15

    the formulae in the book Is n-1 not n

  • @Raycarlaxo
    @Raycarlaxo 7 ปีที่แล้ว +1

    thanks for everything you rock!

  • @lisagood2523
    @lisagood2523 9 ปีที่แล้ว +2

    thank you so much you helped me

  • @AnnaObrien85
    @AnnaObrien85 10 ปีที่แล้ว +3

    Hi! My teacher gave me a formula but it says n-1 on the bottom, instead of just n. Is she wrong or does it alter for some equations? Many thanks, your videos are so helpful!

    • @MrPollockBiology
      @MrPollockBiology  10 ปีที่แล้ว +1

      There are two different standard deviations; one if we are using a sample taken from a population, and one if we are using the entire population.
      AQA does not discriminate if you use one rather than the other.
      Population has n on the bottom
      Sample has n-1 on the bottom
      Thanks for the kind words.

    • @OneShadowHeart
      @OneShadowHeart 9 ปีที่แล้ว +1

      Mr Pollock I don't understand, which one to use?

    • @MrPollockBiology
      @MrPollockBiology  9 ปีที่แล้ว

      Aqa will accept either. If you have one that you're confident with..use it! They will not ask you to calculate SD...but may ask you to interpret results

  • @luvbillypoppy
    @luvbillypoppy 9 ปีที่แล้ว +1

    Do you have a video for spearman rank? Emergency please reply quickly! Or any good video suggestions?

  • @urmans6216
    @urmans6216 6 ปีที่แล้ว +1

    Y r u adding when it's "X-X" not X+X??

    • @proximacentauri2684
      @proximacentauri2684 6 ปีที่แล้ว

      It's the sum of the mean subtracted from all the data values. To get the sum of them all you need to add them together. I know I'm seven months late.