- #1

James Brady

- 103

- 4

Definitions: T = trait, M = males, F = female.

__Given:__

P(T|M) = 0.3

P(T|F) = 0.6

I'm actually having trouble formulating this in mathematical terms even. I'm not sure where the 0.88 comes into play.

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- Thread starter James Brady
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- #1

James Brady

- 103

- 4

Definitions: T = trait, M = males, F = female.

P(T|M) = 0.3

P(T|F) = 0.6

I'm actually having trouble formulating this in mathematical terms even. I'm not sure where the 0.88 comes into play.

- #2

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P(T) doesn't make sense for a continuous trait, and percentiles don't make sense for a binary trait.

- #3

James Brady

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- 4

- #4

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But what doesn't make sense is P(IQ). Everybody has an IQ, it isn't a probabilistic thing. What is probabilistic is the score. So you might say P(IQ>100), but you would never say P(IQ)

- #5

James Brady

- 103

- 4

Oh... So I would formulate it as P(IQ>0.88|M)?

- #6

mfb

Mentor

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You can ask for P(IQ>yourIQ|M) but that's what you want to get, not what you have given.

Where does that come from?Given:

P(T|M) = 0.3

P(T|F) = 0.6

- #7

James Brady

- 103

- 4

@mfb That's completely made up. I'm just trying to get a grasp on how to work with the numbers.

- #8

mfb

Mentor

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- #9

FactChecker

Science Advisor

Gold Member

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That is close. You can have the probability of one event given another event. That would be like P( In88Percentile | M ). If you know the fraction of males in the 88th percentile, that is the answer.Oh... So I would formulate it as P(IQ>0.88|M)?

- #10

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Pretty close. If x is IQ for the 88th percentile then you would write it as P(IQ>x|M).Oh... So I would formulate it as P(IQ>0.88|M)?

So, for convenience (I am on a mobile device) let's say X is "a person has a score for T which is in the 88th percentile or higher". Then your question is to find P(X|M). The way to do that is with Bayes theorem:

P(X|M) = P(M|X) P(X)/P(M)

Can you work it out from there?

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