## Probability: what is difference between two Q's?

Sequences, counting (including probability), logic and truth tables, algorithms, number theory, set theory, etc.
daivinhtran
Posts: 4
Joined: Mon Mar 28, 2011 11:43 pm
Contact:

### Probability: what is difference between two Q's?

Probability Math ???

....................Male ......Female ....Total
Algebra...........21..........13____....34
Geometry.......34 ____..... 26 ___....60
Total............55_____......39____...94

The question is
1,What is the probability that a student is male given that he prefers Algebra?
2,Find the probability of selecting someone who prefers ALgebra and is male.

What is the different betwen 2 question??

maggiemagnet
Posts: 358
Joined: Mon Dec 08, 2008 12:32 am
Contact:

### Re: Probability: what is difference between two Q's?

....................Male ......Female ....Total
Algebra...........21..........13____....34
Geometry.......34 ____..... 26 ___....60
Total............55_____......39____...94

The question is
1,What is the probability that a student is male given that he prefers Algebra?
2,Find the probability of selecting someone who prefers ALgebra and is male.

What is the different betwen 2 question??
For question 2, you need to find the probability of picking somebody male with an algebra preference, out of the total of 94 people. So look for how many males prefer algebra, and divide by the total number of people.

For question 1, you need to start not with all the people, but only with those who prefer algebra. How many is this? Then find the probability that the person is male. How many is this? Divide to find your answer.

daivinhtran
Posts: 4
Joined: Mon Mar 28, 2011 11:43 pm
Contact:

### Re: Probability: what is difference between two Q's?

....................Male ......Female ....Total
Algebra...........21..........13____....34
Geometry.......34 ____..... 26 ___....60
Total............55_____......39____...94

The question is
1,What is the probability that a student is male given that he prefers Algebra?
2,Find the probability of selecting someone who prefers ALgebra and is male.

What is the different betwen 2 question??
For question 2, you need to find the probability of picking somebody male with an algebra preference, out of the total of 94 people. So look for how many males prefer algebra, and divide by the total number of people.

For question 1, you need to start not with all the people, but only with those who prefer algebra. How many is this? Then find the probability that the person is male. How many is this? Divide to find your answer.

So, I do like
21/55 or 21/34