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Difficult Probability Problem

This topic has 2 member replies
jatros123 Junior | Next Rank: 30 Posts Default Avatar
Joined
07 Nov 2006
Posted:
14 messages
Thanked:
2 times

Difficult Probability Problem

Post Sun Feb 18, 2007 1:44 am
Elapsed Time: 00:00
  • Lap #[LAPCOUNT] ([LAPTIME])
    A sample of 1000 persons screened for a certain disease is distributed
    according to height and disease status resulting from a clinical exam
    as follows:

    DISEASE STATUS

    None Mild Moderate Severe Totals
    |-------|---------|------------|----------|
    Tall | 122 | 78 | 139 | 61 | 400
    |-------|---------|------------|----------|
    HEIGHT Med | 74 | 51 | 90 | 35 | 250
    |-------|---------|------------|----------|
    Short | 104 | 71 | 121 | 54 | 350
    |-------|---------|------------|----------|
    300 200 350 150 1000

    What would you estimate from the above table to be the probability
    of being medium or short in height and having moderate or severe
    disease status?

    a. 600/1000 * 500/1000 d. 300/600
    b. 300/500 e. 800/1000
    c. 300/1000

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    jatros123 Junior | Next Rank: 30 Posts Default Avatar
    Joined
    07 Nov 2006
    Posted:
    14 messages
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    2 times
    Post Sun Feb 18, 2007 1:45 am
    oh..sorry the table got screwed..but i hope u can make sense of it anyways

    rajorshic Newbie | Next Rank: 10 Posts Default Avatar
    Joined
    27 Feb 2007
    Posted:
    3 messages
    Post Wed Mar 07, 2007 5:18 am
    Add all the Medium height and Short height
    Medium height = 250
    Short height = 350

    Probability of Medium height = 250/1000 as 1000 is the total no. of people
    Probability of Short height = 350/1000

    Probability of Medium or short is 250/1000 + 350/1000 = 600/1000

    Moderate = 350
    Severe = 150

    Probability of Moderate or Severe is 350/1000 + 150/1000 = 500/1000

    Hence ,Probability of Medium or short and Moderate or severe is
    600/1000 * 500/1000
    Ans: A

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