Cumulative Frequency Curves - What do they mean and how to draw them : ExamSolutions Maths Revision

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  • Опубліковано 15 вер 2024

КОМЕНТАРІ • 33

  • @ImalAkbar1
    @ImalAkbar1 8 років тому +24

    Birds chirping in the background, you must be having a lovely time whilst teaching haha
    thanks for all your effort good Sir

  • @lilmayhem46
    @lilmayhem46 9 років тому +20

    Isn't the value of the upper quartile 176.8 rather than 177.8?

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  9 років тому +1

      dwdw No, I think you missed the fact that each little square represents a 1/2 not 1.

    • @lilmayhem46
      @lilmayhem46 9 років тому +11

      ExamSolutions Sorry I'm pretty sure each little square represents 1 unit? If the intervals of the height is going up in 10s and there's 10 squares between each interval, shouldn't each square be worth one unit? And so the brown line representing the upper quartile is about 1.8 squares after 175, making it 176.8?

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  9 років тому +17

      dwdw Oops! Sorry, you are correct. Hope you understand the method thoughbut are clearly better than me at reading scales.

  • @zoyasaad0
    @zoyasaad0 4 роки тому +1

    this really helped! God bless you!

  • @davidgoodman8469
    @davidgoodman8469 8 років тому +6

    so cumulative frequency graphs are designed to be an aproximate estimate not exact values?

    • @anthony1003
      @anthony1003 4 роки тому +1

      Interval data which uses cumulative frequency graphs have estimates, it's called interval estimation. You don't know the exact values in interval data.

  • @mdjahin99
    @mdjahin99 6 років тому

    Sir! Could you kindly tell me which software do you use to make these videos? They are awesome!

  • @nabibux3608
    @nabibux3608 5 років тому +1

    Thank you

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  5 років тому

      You're always welcome. Thanks for watching and using my vids

  • @samgirl964
    @samgirl964 6 років тому

    Thankyou!

  • @fahimal-huq6867
    @fahimal-huq6867 5 років тому

    thank u sir.

  • @thameskinare
    @thameskinare 8 років тому +2

    Great videos. How can I donate for your effort? Like couple of people have already mentioned it should be 9 students. Because cumulate graph shows =180 = Including 42 to 50 = 9 students. Not sure where i am wrong?

    • @darkskull1155
      @darkskull1155 8 років тому

      +Vipin Ahuja You can donate on his website which is in the description

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  8 років тому +2

      42 students have a height less than 180 cm so there will be another 8 that have a height of 180 cm or more. My answer. Donations are always appreciated to keep this effort going just click here www.examsolutions.net/donation/

  • @lissastanley2
    @lissastanley2 2 роки тому

    I thought when plotting the x axis for cumulative frequency graph you had to plot it using upper boundaries so they 145 would be 135.5 and 155 would be 155.5 etc or ??

  • @noonesherem8782
    @noonesherem8782 3 роки тому

    What if one of the data values recorded was exactly on the class boundary? For example, if the height of one of the students was EXACTLY 165cm, would this data value be put in the class 155-165 , or 165-175?

  • @knowledgeoverlambo5755
    @knowledgeoverlambo5755 8 років тому

    For the estimate of 180cm or more, shouldn't you do 180 - 51? Because the student at 180cm in height (ie the 52nd student) also complies with being 180 cm or more. So the answer would be 9 students?

  • @SilosMOVIE
    @SilosMOVIE 9 років тому

    to calculate Q2 at min 8:00 why did you not do n plus 1 divided by 2? As in other videos right? :S I thought it would be (50+1)/2

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  9 років тому +2

      SilosMOVIE This is continuous data. You only do this if data is discrete.

  • @nisan6937
    @nisan6937 4 роки тому

    I R = Q3 176.8- Q1 165.5=11.3

  • @checkitoutmayne5215
    @checkitoutmayne5215 9 років тому

    it says 180cm or more so wouldnt you include the 180th instead of counting the 8 that are over it.. because 8 students have a hieght of more than a 180cm and the 42nd student is 180cm so thats 9 students? or am i wrong?

  • @mohitl13
    @mohitl13 8 років тому

    Wouldnt
    Q1 be 50/4 = 12.5, but then you round up to the 13th value, as it says in the S1 textbook, and vice versa
    Q3= 12.5*3= 37.5 = 38th value?

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  8 років тому +2

      +M LV You are dealing with continuous data so no. What book are you using that says this?

    • @mohitl13
      @mohitl13 8 років тому

      +ExamSolutions The Edexcel S1 book, it clearly states the rules on finding quartiles, which arent implemented in the same way here.

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  8 років тому +1

      +M LV which page?

    • @mohitl13
      @mohitl13 8 років тому

      +ExamSolutions Page 31, and 51 at the end

    • @ExamSolutions_Maths
      @ExamSolutions_Maths  8 років тому +2

      +M LV That is a method for discrete data as it says on page 51 section 3. You should be reading section 4. I hope that clears that up for you.