Chi-square test for association (independence) | AP Statistics | Khan Academy

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  • Опубліковано 11 вер 2024
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    Chi-square test for association/independence.
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КОМЕНТАРІ • 44

  • @PsyvsPsy
    @PsyvsPsy 3 роки тому +60

    Just a quick note to students following along... take care when using this method, because he is using percentages. Just moving the decimal two places over does NOT WORK unless your grand total is 100. Instead, either convert to a percentage *or* Just multiply row total * column total then divide by grand total. For the first cell, 22*25/100 = 5.5 expected.

    • @PJWB
      @PJWB 3 роки тому +3

      Thank you so much, I was wondering that!

    • @kaiisawesome123
      @kaiisawesome123 2 роки тому

      You goat

    • @jason2044
      @jason2044 2 роки тому +1

      Needed this comment

    • @kenan534
      @kenan534 9 місяців тому

      goated

  • @ankiwikman1218
    @ankiwikman1218 4 роки тому +7

    Khan Academy - love you long time! You deserve so many more likes!

  • @toantruong2581
    @toantruong2581 3 роки тому +5

    This guy deserves a Nobel prize.

  • @hectorponce2012
    @hectorponce2012 3 роки тому +1

    What is the difference between chi square test of proportions vs. chi square of independence?

  • @fgfanta
    @fgfanta 5 років тому +2

    Crystal clear, thanks!

  • @sofiamargarette1979
    @sofiamargarette1979 4 роки тому +1

    How to know whether the result is extreme?

  • @anirudhnegi21
    @anirudhnegi21 5 років тому +1

    thank you so much ! love from india :)

  • @shreejoshi3692
    @shreejoshi3692 Рік тому

    What to do for correlation of 2 ordinal datasets if not monotonic can we do chi square?
    Also how to do it

  • @ramilvillar75
    @ramilvillar75 4 роки тому

    Do you have a video on Chi Square test for more than 2 variables? Thanks and Great job!

  • @giveitago7745
    @giveitago7745 Місяць тому

    Amazing

  • @akberaliebrahim7178
    @akberaliebrahim7178 5 років тому +1

    "...at least this large, or larger". Helpful video nonetheless!

  • @vibhavbawase4652
    @vibhavbawase4652 11 місяців тому

    Understood. Thanx

  • @drewrichter7801
    @drewrichter7801 4 роки тому +4

    You know what they say about big feet.

  • @Andrelavelle28
    @Andrelavelle28 5 років тому +6

    How did he get the p value of 0.018? Do anybody know?

    • @anikethmukhirala3368
      @anikethmukhirala3368 5 років тому

      He most likely looked at a chi-squared distribution. You can find them online.

    • @kmn1794
      @kmn1794 5 років тому

      Take the integral from the test-statistic to the right using the chi-squared PDF for 4 df.

    • @kmn1794
      @kmn1794 5 років тому

      @Aniketh Mukhirala
      That's unlikely - and I have looked. To tabulate p-values to 3 dp requires a 1000 columns for each chi-squared CDF (degree of freedom).

  • @esperanzazagal7241
    @esperanzazagal7241 3 роки тому

    Hi Sal, is the p-value at 9:14 the p-value from the chi-critical or from the hypothesis test? One more question, would we ever do run a chi-square per row instead of for all data cells? Thank you for your great videos!

  • @tanajidivtiwad9336
    @tanajidivtiwad9336 6 років тому

    Thanks Best explain of chi square test

  • @ayushkumarsingh8020
    @ayushkumarsingh8020 3 роки тому

    best explanation!

  • @nai_._ya
    @nai_._ya 4 роки тому +6

    The p value according to the Chi square table for a DF of 4 and significance level of 0.05 is 9.488 but here it is 0.018. Am I missing something?

    • @siddharthmagadum16
      @siddharthmagadum16 3 роки тому +1

      yeah, same question, anyone pls tell me...

    • @rugerbird
      @rugerbird 3 роки тому +2

      In A-level maths we comapre the chi-squared value, but here he has compared the p value instead. 9.488 is a chi-squared value which came from DF4 and p0.95. I assume he used his calculated value for chi-square and DF4 to come up with a 2nd p value to compare. Not possible on the chi-squared table I have for A-level maths in the UK, but probably easy enough with the right software.

  • @naiameyers4725
    @naiameyers4725 7 місяців тому

    how do you find a p value using a calculator???

  • @gideonvalpoort4235
    @gideonvalpoort4235 3 роки тому

    Verry urgent question! What about when looking at differences? How do you interpret the p value then? Doe this mean that there ia a significant difference between groups?

  • @shinnelleogilvie9463
    @shinnelleogilvie9463 4 роки тому +1

    Did anyone recognize that when he as calculating the expected values he said multiply by 100 rather than divide by 100?

    • @ioannismalekakis2997
      @ioannismalekakis2997 4 роки тому +2

      That's because he is multiplying frequencies and not absolute numbers.

  • @madannikalje760
    @madannikalje760 4 роки тому

    Clear 👌👍

  • @somcana
    @somcana 6 років тому +1

    fo you mean divide by hundred.

  • @andishen933
    @andishen933 5 років тому +1

    how did he make up the x=0.05?

    • @yaningwu5832
      @yaningwu5832 5 років тому +3

      andi shen When thé significance level isn't given, you can assume that x = 0.05.

    • @perpetualyamba2362
      @perpetualyamba2362 4 роки тому +1

      thats the standard level of significance if not given

  • @luisv.7518
    @luisv.7518 5 років тому +1

    How will you get the significance level?

    • @anikethmukhirala3368
      @anikethmukhirala3368 5 років тому +1

      You make up your own. The most common is 0.05 in statistics, but medical studies often use 0.01.

  • @name.615
    @name.615 3 роки тому

    why it is not in urdu

  • @michaengtrash9194
    @michaengtrash9194 4 роки тому

    how did you get the p value?

    • @chineme13
      @chineme13 2 роки тому

      @Tim DaHuman but how did he get there? it seems like he plucked 0.018 out of no where and I am very confused