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Author8 Posts
  #1

a mother has waardenburg syndrome{AD}her husband is unaffected and they plan to have a family with three children.what is the probability that one of the three children will be affected?
A.1/8
B.1/4
C.3/8
D.1/3
E.7/8


A?

  #2

C

Assume her 3 children named X, Y, Z

Each child has 1/2 chance of disease and 1/2 chance free of disease.

The probability that one of the three children will be affected= X with disease but other 2 without disease + Y with disease but other 2 without disease + Z with disease but other 2 without disease = 1/2*1/2*1/2 + 1/2*1/2*1/2 +1/2*1/2*1/2=3/8

All 3 have disease = 1/2*1/2*1/2=1/8

All 3 free of disease = 1/2*1/2*1/2=1/8

2 of 3 have disease 1-3/8-1/8-1/8=3/8




___________________
The Key to Succeed is Patience.

  #3

i multiplied 1/2 to the 3rd power to get 1/8 comments please.

___________________
Smell the coffee! "Is That an Osler move??"

  #4

I agree with robin082006.

In effect, 1/8 is only the probability that the first child will be affected.

We have to consider also the other two possibilities!


  #5

I don't understand it!!!

  #6

Hey robin. I've been always appreciating your explanations. Thanks . My exam is in two days. Good luck to you. Wish you the best.

  #7

In Two days?

Good luck to you.

Give yor experience after the exam.


___________________
The Key to Succeed is Patience.

  #8

Good luck, nadiabarati.

Best wishes.












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