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Project maths - help required!!!!

  • 15-04-2014 3:42pm
    #1
    irishlassy1
    Registered Users, Registered Users 2 Posts: 16 ✭


    Hi guys... So I'm doing this question from the educate.ie sample papers and I'm really stuck on this question based on a normal distribution curve. The curve is drawn for you, and you have to get the median, UQ, LQ and IQ range all of which I've done. Now I have to find the standard deviation of the curve and I'm not sure what to do?


Comments

  • #2
    lostatsea
    Registered Users, Registered Users 2 Posts: 320 ✭✭lostatsea


    What is the paper and question number?


  • #3
    irishlassy1
    Registered Users, Registered Users 2 Posts: 16 ✭irishlassy1


    lostatsea wrote: »
    What is the paper and question number?

    It's the educate.ie Sample 4, Paper 2 Q4... Thanks so much!


  • #4
    lostatsea
    Registered Users, Registered Users 2 Posts: 320 ✭✭lostatsea


    Solution to Question 4


  • #5
    irishlassy1
    Registered Users, Registered Users 2 Posts: 16 ✭irishlassy1


    lostatsea wrote: »
    Solution to Question 4

    Thank you ever so much, I've been at it hours now!!!!


  • #6
    irishlassy1
    Registered Users, Registered Users 2 Posts: 16 ✭irishlassy1


    irishlassy1 wrote: »
    Thank you ever so much, I've been at it hours now!!!!

    May seem like a stupid question but where does the 0.675 come from in part c?


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  • #7
    lostatsea
    Registered Users, Registered Users 2 Posts: 320 ✭✭lostatsea


    You need to look up the z scores for standard normal distributions on page 36 of the Formulae and Tables book.


  • #8
    irishlassy1
    Registered Users, Registered Users 2 Posts: 16 ✭irishlassy1


    lostatsea wrote: »
    You need to look up the z scores for standard normal distributions on page 36 of the Formulae and Tables book.

    Did that but I don't think they match?


  • #9
    lostatsea
    Registered Users, Registered Users 2 Posts: 320 ✭✭lostatsea


    Go to 0.7486 in the table on page 36. This corresponds to a z score of 0.67. 0.75 is about halfway between 0.7486 and 0.7517 giving an approximate z score of 0.675.


  • #10
    irishlassy1
    Registered Users, Registered Users 2 Posts: 16 ✭irishlassy1


    lostatsea wrote: »
    Go to 0.7486 in the table on page 36. This corresponds to a z score of 0.67. 0.75 is about halfway between 0.7486 and 0.7517 giving an approximate z score of 0.675.

    God I do feel a little daft. Thanks so much for the help :-)


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