Math experts also scuba right?

[nkw5]

I need help with this probabily problem:

50% of an age group say they work full-time. 41% say they go to school. 19% say they work and go to school. What is the probability that by randomly choosing someone in this age group that you will pick someone who is working full-time or going to school or both?

Please tell me the answer and how to solve this. It's driving me crazy!

 

[Walter]

You'd need more information to answer the question. What is the overlap of the various groups?

 

[wcl]

I need help with this probabily problem:

50% of an age group say they work full-time. 41% say they go to school. 19% say they work and go to school. What is the probability that by randomly choosing someone in this age group that you will pick someone who is working full-time or going to school or both?

Please tell me the answer and how to solve this. It's driving me crazy!

Hi,

Clarification is required:

Does "50% of an age group say they work full-time" really mean "50% of an age group say they work full-time AND do not go to school", or "50% of an age group say they work full-time REGARDLESS of whether they also go to school or not"?

That is to ask, are the 3 pieces of quantitative information all disjoint (set "work", set "school", set "both", all distinct), or are the first two independent and the third (work and school percentage) additional correlation information about the first two (set "work", set "school", set "work" <intersection> set "school")?

After that, the approach is to determine the probability of randomly selecting someone who neither works nor goes to school, and the answer to your question is the complementary probability.

Cheers,

Walter

 

[jonnythan]

I need help with this probabily problem:

50% of an age group say they work full-time. 41% say they go to school. 19% say they work and go to school. What is the probability that by randomly choosing someone in this age group that you will pick someone who is working full-time or going to school or both?

Please tell me the answer and how to solve this. It's driving me crazy!

Think of it in terms of actual numbers.

If you have 100 people, 50 of them work, 41 of them are in school. 19 of them do both, so 19 out of these "91" people don't actually exist. This gives you 50 + 41 - 19 = 72 people who are at work or school.

Here is an awful drawing that might help.

 

[jonnythan]

Oh, so if 72 people are doing something, that leaves 28 lazy butts, and your chances are 72% you won't choose a lazy butt

 

[jonnythan]

Hi,

Clarification is required:

Does "50% of an age group say they work full-time" really mean "50% of an age group say they work full-time AND do not go to school", or "50% of an age group say they work full-time REGARDLESS of whether they also go to school or not"?

That is to ask, are the 3 pieces of quantitative information all disjoint (set "work", set "school", set "both", all distinct), or are the first two independent and the third (work and school percentage) additional correlation information about the first two (set "work", set "school", set "work" <intersection> set "school")?

After that, the approach is to determine the probability of randomly selecting someone who neither works nor goes to school, and the answer to your question is the complementary probability.

Cheers,

Walter

You're reading way to much into it. 50% say they work, not 50% say they ONLY work.

Besides, if they were independent, you'd have 110%, so they can't possibly be independent. It's much simpler than you seem to think

 

[Walter]

It's simple, but there still isn't enough information to answer the question.

 

[jonnythan]

It's simple, but there still isn't enough information to answer the question.

Yes there is.

And I answered it.

 

[Don Burke]

91 out of 100 either work full time or go to school or do both.

The probability of one selected at random being in one of the three groups is 91 in 100.

The 19% is meaningless for this purpose.

I need help with this probabily problem:

50% of an age group say they work full-time. 41% say they go to school. 19% say they work and go to school. What is the probability that by randomly choosing someone in this age group that you will pick someone who is working full-time or going to school or both?

Please tell me the answer and how to solve this. It's driving me crazy!

 

[jonnythan]

91 out of 100 either work full time or go to school or do both.

The probability of one selected at random being in one of the three groups is 91 in 100.

The 19% is meaningless for this purpose.

The 19% isn't meaningless. The 19% indicates that 19 of your 91 people are duplicates. There's no way to have 50 people who work, 41 who go to school, 19 who do both, and only 9 who do neither.