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Probability

by Abdulla » Tue Dec 16, 2008 8:04 pm
A medical researcher must choose one of 14 patients to receive an experimental medicine called Progain. The researcher must then choose one of the remaining 13 patients to receive another medicine called Ropecia. Finally then researcher administers a placebo to one of the remaining 12 patients. All choices are equally random. If Donald is one of the 14 patients, what is the probability that Donald receives either Progain or Ropecia?


OA is [spoiler]1/14+1/14=1/7[/spoiler]
Last edited by Abdulla on Tue Dec 16, 2008 9:45 pm, edited 1 time in total.
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Re: Probability

by logitech » Tue Dec 16, 2008 9:13 pm
Donald received Progain: 1/14

Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/14

what is the probability that Donald receives either Progain or Ropecia?

1/14+1/14 = 1/7 ( Not 1/17) :)
Last edited by logitech on Wed Dec 17, 2008 8:34 am, edited 1 time in total.
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by Abdulla » Tue Dec 16, 2008 9:45 pm
I really neeeeeeeeeeeeeeeeeeeeeeeeeeeeeed Vegas
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Re: Probability

by gmatman1 » Wed Dec 17, 2008 2:22 am
logitech wrote: Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4
I am sure you meant 1/14 instead of 1/4.
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Re: Probability

by Abdulla » Wed Dec 17, 2008 3:30 am
logitech wrote:Donald received Progain: 1/14

Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4

what is the probability that Donald receives either Progain or Ropecia?

1/14+1/14 = 1/7 ( Not 1/17) :)


Not only me :lol:
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Re: Probability

by vivek.kapoor83 » Wed Dec 17, 2008 5:35 am
logitech wrote:Donald received Progain: 1/14

Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4

what is the probability that Donald receives either Progain or Ropecia?

1/14+1/14 = 1/7 ( Not 1/17) :)
could not understan
Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4



these are same pls explain the step
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Re: Probability

by dmateer25 » Wed Dec 17, 2008 6:10 am
vivek.kapoor83 wrote:
logitech wrote:Donald received Progain: 1/14

Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4

what is the probability that Donald receives either Progain or Ropecia?

1/14+1/14 = 1/7 ( Not 1/17) :)
could not understan
Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4



these are same pls explain the step
I think you misunderstood what logitech typed.

The probability that Donald receives Ropecia is: The probability the he wasn't chosen for Progain x the probability that Donald was chosen for Ropecia.



The researcher chooses a person for Progain first. Therefore there is a 1/14 chance that it will be Donald. There is a 13/14 chance that it won't be Donald.

In order for the Donald to be chosen by the researcher for Ropecia, he must NOT be chosen by the researcher for Progain. Donald chosen for Ropecia is dependent on whether he was chosen for Progain.


So The probability that Donald receives Ropecia is: 13/14(wasn't chosen for Progain) x 1/13 (he was chosen for Ropecia) = 1/14

Please let me know if I made it too difficult to understand!
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Re: Probability

by logitech » Wed Dec 17, 2008 8:35 am
dmateer25 wrote:
vivek.kapoor83 wrote:
logitech wrote:Donald received Progain: 1/14

Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4

what is the probability that Donald receives either Progain or Ropecia?

1/14+1/14 = 1/7 ( Not 1/17) :)
could not understan
Donald received Ropecia: Donald did not receive Progains x Donal Received Ropecia = 13/14 x 1 /13 = 1/4



these are same pls explain the step
I think you misunderstood what logitech typed.

The probability that Donald receives Ropecia is: The probability the he wasn't chosen for Progain x the probability that Donald was chosen for Ropecia.



The researcher chooses a person for Progain first. Therefore there is a 1/14 chance that it will be Donald. There is a 13/14 chance that it won't be Donald.

In order for the Donald to be chosen by the researcher for Ropecia, he must NOT be chosen by the researcher for Progain. Donald chosen for Ropecia is dependent on whether he was chosen for Progain.


So The probability that Donald receives Ropecia is: 13/14(wasn't chosen for Progain) x 1/13 (he was chosen for Ropecia) = 1/14

Please let me know if I made it too difficult to understand!
I apologize for not explaining more clearly. Thanks DM25!

And also I corrected my 1/4 typo.
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by vivek.kapoor83 » Thu Dec 18, 2008 4:07 am
thanx dematteer...gr8 explanation
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