Confidence Intervals for Sample Proportions

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  • Опубліковано 8 кві 2013
  • How to find the sample proportion confidence interval

КОМЕНТАРІ • 70

  • @ladyjulien
    @ladyjulien 4 роки тому +31

    this video is more helpful than the ones I found in khan academy. you just saved my grades

    • @cynthia9957
      @cynthia9957 4 роки тому +1

      You're right...I understand this video better as well... life saver 😭😭❣️😘

    • @danielschaben
      @danielschaben  3 роки тому +1

      So glad it was helpful

    • @cmcatholic1798
      @cmcatholic1798 3 роки тому

      Yeah true😂👍👍

  • @jadalong9587
    @jadalong9587 3 роки тому +6

    Something is clearly wrong with this damn textbook for my class lmaooo. This was 10x better than what my teacher is teaching smh

    • @danielschaben
      @danielschaben  3 роки тому +1

      Glad I can help. If there are things you can't find, let me know. I will make videos if your having problems with things

  • @eunicemartinez3716
    @eunicemartinez3716 6 років тому +5

    Thank you! This helped so much 😊

  • @katrinasparks3708
    @katrinasparks3708 Рік тому

    This was the best breakdown of this question I've seen this far on the internet.

    • @danielschaben
      @danielschaben  Рік тому

      Wow. Thanks for the comment. I need to get back into making these videos. Been a while since I've made any

  • @SWEETCHIANTELLE
    @SWEETCHIANTELLE 2 роки тому +1

    youre probably the only one that explained this so well. THANK YOUUUU SO MUCHHHHHHH

  • @iamheqiang
    @iamheqiang 8 років тому

    thank you so much!!! saved my life

  • @gladysoyola
    @gladysoyola 3 роки тому +2

    THANK YOU THANK YOU THANK YOU THANK YOU! I HAVE BEEN BREAKING MY SKULL TO DO THIS AND THIS VIDEO IS AMAZING!!!!!!!!!!!!!

    • @danielschaben
      @danielschaben  3 роки тому

      I'm glad I could help. I'm not sure how communications work on UA-cam but if you have other areas that you need videos for, let me know. I would sure make more for you. Thanks for the comment!

  • @carlosseminario9664
    @carlosseminario9664 10 років тому +1

    Clear make it easier . thank you!

  • @angelasmith1122
    @angelasmith1122 4 роки тому +7

    Thank you so much. I don’t know what kind of example this lesson was giving but this helped me entirely! Thank you. I even learned how to use the normal standard table that was never even taught 🤷🏽‍♀️ the example from my class was ridiculously over done that made it very confusing. Again thank you, you’re awesome😊

  • @MWAKACHAKAWA
    @MWAKACHAKAWA Місяць тому

    Very helpful explanation, thank you so much!

  • @nikeett
    @nikeett 11 років тому

    Keep up the good work!!!i gota test tomorw...this simple thing really helpd me...thankx

  • @Sourblob
    @Sourblob 8 років тому +3

    I have a question: why, when one is testing the difference between two proportions, does one take a weighted mean estimate of the sample proportions to find the test value for the difference of the true proportions distribution but when one uses the confidence interval formula for the difference between two proportions, one estimates the margin of error by using just the sample proportions without taking their weighting average?

  • @cregghinson8312
    @cregghinson8312 3 роки тому

    Exactly what I needed. Thanks

  • @AbdirahmanAbdullahi6545
    @AbdirahmanAbdullahi6545 9 років тому

    thank you

  • @AJ-et3vf
    @AJ-et3vf 2 роки тому +1

    Awesome video. Thank you.

    • @danielschaben
      @danielschaben  2 роки тому

      Thanks for the comment. Glad it was useful!

  • @divinest
    @divinest 6 років тому

    thanks mate

  • @roseytb4092
    @roseytb4092 2 роки тому

    Hi I don't understand how to find ic 95 in this kind of exercise. could you help me?
    In the article, the difference in 28-day mortality between the Lopinavir / Ritonavir group and the Standard Care group was -5.8%. Mortality was rated as similar in both groups. Among the following fictitious results, which one or which will lead us to conclude that the mortality between the two groups is similar? (The 95% confidence interval is given in square brackets) Result A:
    Mortality difference: -16% [ -30%; -2%]
    Result B:
    Mortality difference: -5.8% [-11%; -0.6%]
    Result C: Mortality difference:
    -2% [-17%; 13%]
    Result D: Mortality difference: -0.5% [-3%; 2%]

  • @p2p2p2p2p2p
    @p2p2p2p2p2p 3 роки тому

    so clear thank you

  • @johnliu977
    @johnliu977 2 роки тому

    Thank you!

  • @Riasat202
    @Riasat202 10 років тому

    Thanks! :)

    • @ramirorios880
      @ramirorios880 4 роки тому

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  • @Johnny87Au
    @Johnny87Au 7 років тому +10

    Why is it when i download the Z tables i cant find .0450? Have they changed the Z tables since now or ??

  • @Iliasduty
    @Iliasduty 2 роки тому

    yeah but how do you find the equation?

  • @jadalong9587
    @jadalong9587 3 роки тому +1

    Is there a link or pdf to this z-table? Because for whatever reason, the z-tables I find online aren't as accurate as this one and it keeps skewing my results.

    • @danielschaben
      @danielschaben  3 роки тому

      That surprising. I figured all z tables were the same. Maybe I need to redo this video with current resources. I can't publish a pdf of what I used because it would break copywrite. I can tell you it comes from author Bluman and is called "Elementary Statistics A step by step Aproach"

    • @jadalong9587
      @jadalong9587 3 роки тому +1

      @@danielschaben yeah, all the ones I’m seeing has different values in different places than on yours and it keep causing me to get the wrong answers. Even the one in my textbook. But when I used yours through this video, it worked perfectly and I got the correct answer

    • @danielschaben
      @danielschaben  3 роки тому

      @@jadalong9587 check your tables. Make sure you are using the same one that has the same area under the normal curve as mine. Sounds like you are on the wrong table type

  • @commonlove2001
    @commonlove2001 8 років тому +5

    Daniel the thumps are distracting

  • @teddyw.charawa8989
    @teddyw.charawa8989 4 роки тому +1

    You have nailed it?

  • @childrenofthanos2413
    @childrenofthanos2413 2 роки тому +1

    Sir quick question how did u get the answer 0.024??

    • @danielschaben
      @danielschaben  2 роки тому

      I plugged that zscore times the standard deviation into a calculator. Plug that mess in and see if you get the same thing. Thanks for the comment

  • @hounamao7140
    @hounamao7140 7 років тому +10

    why did you take alpha=90 ? I thought 90 = 1 - alpha, shouldnt alpha be 10 ?

    • @zincmusic24
      @zincmusic24 5 років тому +4

      he's bored. his z table values r wrong tooo. it has to be 10 yea

  • @nandikolmathshashi
    @nandikolmathshashi 7 років тому

    i have question sir which i was not able to solve my mind got blast but i didnt find satisfied answer question is
    A random sample of 700 oranges was taken from a large segment and 100 found to be defective construct the 95℅ confidence limit for ℅ of number of oranges in segment

    • @danielschaben
      @danielschaben  7 років тому +1

      Here goes. Sorry been sick. the z-score for 95% confidence is 1.96. The standard error is sqrt((1/7)(6/7)/700) = 0.0132....
      (1/7) - 1.96(0.0132)

    • @nandikolmathshashi
      @nandikolmathshashi 7 років тому

      Thank you very much sir but which formula to so I can understand it and resolve it without reference to learn

    • @danielschaben
      @danielschaben  7 років тому +1

      So we are 95% confident that the true proportion of bad oranges is between 0.12 and 0.17.

    • @danielschaben
      @danielschaben  7 років тому

      The formula i used is at 4:41 of this video and around 7:00. 4:41 is the general formula. 7:00 is the formula applied to the example I gave.

    • @nandikolmathshashi
      @nandikolmathshashi 7 років тому

      Thank you very much sir
      Do you mind if i keep asking you for solution of problem that which I can't understand

  • @Annchene7
    @Annchene7 7 років тому

    A random sample of 49 lunch customers was taken at a restaurant. The average amount of time the customers in the sample stayed in the restaurant was 45 minutes with a standard deviation of 14 minutes. 1. Construct a 90% confidence interval for the true average amount of time customers spent in the restaurant? 2. Construct a 99% confidence interval for the true average amount of time customers spent in the restaurant? 3. Dscuss why the answers in Parts (1) and (2) are different? 4. With a .95 probability, how large of a sample would have to be taken to provide a margin of error of 2.5 minutes or less? Entire solution

  • @TheMatttm
    @TheMatttm 9 років тому +5

    Why did you use z sub .45? It is a/2, and since confidence was .9, alpha'd be .1. Hence, wouldn't you use .05?

    • @geoffreywoodland1672
      @geoffreywoodland1672 9 років тому +1

      Matt Maloney I was thinking the same thing.

    • @geoffreywoodland1672
      @geoffreywoodland1672 9 років тому

      Thanks for the explanation Dan! Great video!

    • @fly869
      @fly869 7 років тому

      Matt Maloney ?

    • @TheMatttm
      @TheMatttm 7 років тому

      ?

    • @fly869
      @fly869 7 років тому

      Matt Maloney did you understand why? I have the same question in mind

  • @MONEYSNEAKERS
    @MONEYSNEAKERS 9 років тому

    No clue

  • @nandikolmathshashi
    @nandikolmathshashi 7 років тому

    please some one help me how to solve below question I am not getting it from so many days

  • @andreameigs1261
    @andreameigs1261 2 роки тому

    What is alpha???

    • @danielschaben
      @danielschaben  2 роки тому

      It's been a while since I've taught this, but essentially it is the percent error we arbitrarily accept as ok. I will think through a better explanation

  • @kinmokusei2007
    @kinmokusei2007 5 років тому

    Not .045, it's .450

    • @danielschaben
      @danielschaben  5 років тому

      could you get me a time stamp? I cant find where your meaning