Probability math question?

[Minotar]

Here's a probability question for anyone who cares to take a stab...

5% of all males in a population are obese
0.25% of all females in a population are obese

If 54% of a population are females, then what is the probablilty, when a person is chosen at random, for them to be obese?

I was initially thinking it would just be the sum of the probabilities, but I am not sure if this is the correct thinking? Anyone have some insight?

 

[joshmroest]

There would be a 2.435% that an obese person would be chosen. I took a sample size of 1 million. Out of that, 540,000 will be female and 460,000 will be male. Out of the 540,000 females, only 1,350 will be obese while 23,000 of the 460,000 males will be obese. That is a total of 24,350 obese people out of 1,000,000. That is how I got the 2.435%.

 

[Inspector Jihad]

^^looks liek a right answer

 

[Navid]

Female obese population percentage would be 0.25% multiplied by 54% = 0.135%.
Male obese population percentage would be 5% multiplied by 46% = 2.3%.
Obese population percentage would be the sum of the two = 0.135% + 2.3% = 2.435%.

 

[joshmroest]

That's what I did...just the long way.

 

[Minotar]

Thanks for the help I just wasn't sure if I should add the probs or multiply things out. You guys cleared it up for me... Thanks!

 

[joshmroest]

No problem...