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    Probability Normal Distribution

    Uploaded by

    Ashraf Zaman

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Probability Normal Distribution

    Uploaded by

    Ashraf Zaman
    5 views2 pages

    Original Title

    Probability_Normal_distribution.docx

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    © © All Rights Reserved

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    PDF, TXT or read online from Scribd

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    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    5 views2 pages

    Probability Normal Distribution

    Uploaded by

    Ashraf Zaman

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 2

    Q.

    The manager of a small postal substation is trying to quantify the variation in the weekly
    demand for mailing tubes. She has decided to assume that this demand is normally distributed.
    She knows that on average 100 tubes are purchased weekly and that 90 percent of the time,
    weekly demand is below 115.

    A) What is the standard deviation of this distribution?

    B) the manager wants to stock enough mailing tubes each week so that the chance of running out of
    tubes is not higher than 0.05. Assuming you in place of manager decide the stock level.

    Ans:
    90%
    a)

    Z-table for 0.40=1.28

    Rejection region

    m
    er as
    0.50 0.40

    co
    Z=0 Z=1.28

    eH w
    µ=100 X1=115

    o.
    The value of Z at 0.40 is 1.28 [from Z-table] one-tail
    rs e
    ou urc
    X 1−μ
    Z =
    σ
    o

    115−100
    1.28 =
    aC s

    σ
    v i y re

    σ = 11.72

    b)
    ed d

    95%
    ar stu

    Rejection region
    sh is

    0.50 0.45
    Th

    Z=0 Z=1.64
    µ=100 X2=?

    X 2−μ
    Z =
    σ

    X 2−100
    1.64 =
    11.72

    X2 = 120

    This study source was downloaded by 100000771688659 from CourseHero.com on 12-04-2021 05:04:06 GMT -06:00

    https://www.coursehero.com/file/54265332/Probability-Normal-distributiondocx/
    m
    er as
    co
    eH w
    o.
    rs e
    ou urc
    o
    aC s
    v i y re
    ed d
    ar stu
    sh is
    Th

    This study source was downloaded by 100000771688659 from CourseHero.com on 12-04-2021 05:04:06 GMT -06:00

    https://www.coursehero.com/file/54265332/Probability-Normal-distributiondocx/
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