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Help with S1 question (Histograms)?

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    • Thread Starter

    In a particular week, a dentist treats 100 patients. The length of time, to the nearest minute , for each patient's treatment is summarised below.

    Time(minutes): 4 - 7
    Number of patients: 12

    Time(minutes): 8
    Number of patients: 20

    Time(minutes): 9 - 10
    Number of patients: 18

    Time(minutes): 11
    Number of patients: 22

    Time(minutes): 12-16
    Number of patients: 15

    Time(minutes): 17-20
    Number of patients: 13

    Draw a histogram to illustrate these data.

    The only bit which I don't understand is where the class width is 0 i.e. in the 8th and 11th minute. What's the frequency density for these 2?

    for 8 the width is 1, from 7.5 to 8.5

    What did you think the width was for 4-7?
    • Thread Starter

    (Original post by TenOfThem)
    What did you think the width was for 4-7?
    3 ain't it? So the frequency density is 4 since 12/3 = 4.

    (Original post by Dr.Pwepper)
    3 ain't it? So the frequency density is 4 since 12/3 = 4.

    the width is 7.5 - 3.5 = 4

    So the density is 3
    • Thread Starter

    (Original post by TenOfThem)

    the width is 7.5 - 3.5 = 4

    So the density is 3
    Ah yes, I forgot about the upper and lower bound.



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