For those who like Math problems

[FurbiesAndBeans 10+ year member]

Read this problem and I thought it was really interesting (not because of the info but more about how to figure it out).

Estimate the probability that a woman with a positive mammogram actually has breast cancer, even though she’s in a low-risk group: 40 to 50 years old, with no symptoms or family history of breast cancer.

Assume the following:

The probability that one of these women has breast cancer is 0.8 percent. If a woman has breast cancer, the probability is 90 percent that she will have a positive mammogram. If a woman does not have breast cancer, the probability is 7 percent that she will still have a positive mammogram. Imagine a woman who has a positive mammogram. What is the probability that she actually has breast cancer?

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[Slo_Ride 5,000+ posts]

you're retarded

 

[jco1385 5,000+ posts]

97%

 

[RAM_Designs 5,000+ posts]

1:10.64?

I haven't had a math class in a while... //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[whitedragon551 5,000+ posts]

The OP is way off. Its not even right in the first place. .8% and 80% are very different things. Going on the OP's logic it should be between .8% and 90% not between 70% and 90%.

 

[RAM_Designs 5,000+ posts]

The OP is way off. Its not even right in the first place. .8% and 80% are very different things. Going on the OP's logic it should be between .8% and 90% not between 70% and 90%.

It made sense to me. .8 out of every 100 women will have breast cancer, testing positive 90% of the time. Out of the remaining 99.2 women who do not have cancer, 7% will still test positive.

 

[FurbiesAndBeans 10+ year member]

The OP is way off. Its not even right in the first place. .8% and 80% are very different things. Going on the OP's logic it should be between .8% and 90% not between 70% and 90%.

What's way off? I think you're not understanding. If i spoon feed you then that takes the fun out of the problem. The probability of .8%-90% is not a definite answer. There is definitely a single number that you can derive //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[FurbiesAndBeans 10+ year member]

It made sense to me. .8 out of every 100 women will have breast cancer, testing positive 90% of the time. Out of the remaining 99.2 women who do not have cancer, 7%% will still test positive.

You're on the right track.

 

[jco1385 5,000+ posts]

when you get done playin with us, i'd actually like to see how you work it out, so i can actually learn something on this site. i do math everyday, but not to that extent.

 

[whitedragon551 5,000+ posts]

when you get done playin with us, i'd actually like to see how you work it out, so i can actually learn something on this site. i do math everyday, but not to that extent.

This. I just passed advanced stats with a 98%. I dont think Im the one who needs spoon feeding here.

 

[FurbiesAndBeans 10+ year member]

It made sense to me. .8 out of every 100 women will have breast cancer, testing positive 90% of the time. Out of the remaining 99.2 women who do not have cancer, 7%% will still test positive.

This is your hint guys.

 

[RAM_Designs 5,000+ posts]

1:10.64?

I haven't had a math class in a while... //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

So I take it this isn't right?

You've got to find the total number of women who test positive.

.8 x 90% = .72 women who have cancer and test positive

99.2 x 7% = 6.944 women who do not have cancer and test positive

-----------------

7.664 total women who test positive for cancer

Chances of it be a woman who actually has cancer is .72 in 7.664, or 1:10.6444444, so one in every 10.64 women who test positive actually have breast cancer.

 

[FurbiesAndBeans 10+ year member]

So I take it this isn't right?
You've got to find the total number of women who test positive.

.8 x 90% = .72 women who have cancer and test positive

99.2 x 7% = 6.944 women who do not have cancer and test positive

-----------------

7.664 total women who test positive for cancer

Chances of it be a woman who actually has cancer is .72 in 7.664, or 1:10.6444444, so one in every 10.64 women who test positive actually have breast cancer.

That is exactly correct. I didnt realize at first it was a ratio. I thought you were just saying a random time lol.

Comes out to around 9%.

 

[RAM_Designs 5,000+ posts]

That is exactly correct. I didnt realize at first it was a ratio. I thought you were just saying a random time lol.
Comes out to around 9%.

So wtf do I win?

 

[RAM_Designs 5,000+ posts]

My paypal is RyanM923@aol.com if anyone wants to donate to my college fund in order to put my superior math skills to good use. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif