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? asked in Science & MathematicsMathematics · 7 years ago

Can someone help me with this probability question?

The chart reads:

Positive test result(pregnancy is indicated)

-subject is pregnant; 80

-subject is not pregnant; 3

Negative test result(pregnancy is not indicated)

-subject is pregnant; 5

-subject is not pregnant; 11

The questions says: if 2 different subjects are randomly selected, find the probability that they both test positive for pregnancy

I know the answer which is .702 but I don't know how to get that answer. So can some one help me work through it

1 Answer

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  • M3
    Lv 7
    7 years ago
    Favorite Answer

    although i have got the answer you seek, this is a poorly worded question without comprehensive data

    there are a total of 99 women of whom 83 test +ve

    if you choose 2 randomly,

    P(both +ve) = 83/99 *82/88 = .702

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