Statistics problem:

[CDM]

I can't figure out what I'm missing... and I'm wasting too much time trying to figure out what it is!! Could someone help?

P(A) = 0.3
P(B) = 0.5

P(A u B) = 0.6

P(A/B) = 0.4 <---- HOW are they getting 0.4???

Thanks a million

[snazzlefrag]

Originally Posted by CDM

I can't figure out what I'm missing... and I'm wasting too much time trying to figure out what it is!! Could someone help?

P(A) = 0.3
P(B) = 0.5

P(A u B) = 0.6

P(A/B) = 0.4 <---- HOW are they getting 0.4???

Thanks a million

Can you give us the entire question?

Thanks,
Snazzlefrag

[CDM]

The question is - what is the probability of A given B. P(A/B)
So - If P(A) = 3 and P(B)= 0.5, and P(A u B) = 0.6, then what is the probability of A given B?

The answer is 0.4000 --.

[snazzlefrag]

Originally Posted by CDM

The question is - what is the probability of A given B. P(A/B)
So - If P(A) = 3 and P(B)= 0.5, and P(A u B) = 0.6, then what is the probability of A given B?

The answer is 0.4000 --.

CDM,

Okay, here's what I get...

----------------
P(A) = 0.3
P(B) = 0.5
P(A u B) = 0.6
P(A/B) = 0.4
----------------

P(A/B) = P(B/A) * P(A) / P(B)
P(A/B) = 0.666666666666667 * 0.3 / 0.5 = 0.4

Hope that helps,
Snazzlefrag

[CDM]

thank you! I'll study on this and figure out where I went wrong... Peace

[snazzlefrag]

Originally Posted by CDM

thank you! I'll study on this and figure out where I went wrong... Peace

CDM,

Are you studying for DANTES Statistics? If so, this question goes beyond what you actually need to know for the exam.

Just FYI,
Snazzlefrag

[CDM]

Originally Posted by snazzlefrag

CDM,

Are you studying for DANTES Statistics? If so, this question goes beyond what you actually need to know for the exam.

Just FYI,
Snazzlefrag

ARE YOU SERIOUS??!! Maybe there actually IS hope for me then!!

[snazzlefrag]

Originally Posted by CDM

ARE YOU SERIOUS??!! Maybe there actually IS hope for me then!!

Absolutely!

This question required the use of Baye's Theorem to solve. I don't recall any similar question on the exam. Any question that requires complex or nuanced mathematical calculation is unlikely to appear on this exam. Of course, the study of statistics involves math; but this exam is NOT a math exam in and of itself. Remember that! If ever you do come across a question that would take you ten minutes to solve using a complex mathematical equation, you should SKIP that question altogether...because it isn't worth the time and effort. There will be plenty of other questions which can be answered within a second or two...and the easier question will be worth exactly the same points as the complex equation question.

I say this to try and ease your mind a little. Don't sweat the really complicated stuff.

You really need to make sure you have mastered ALL THE BASICS, and then add in some of the slightly more complex topics as you feel truly comfortable with the basics. Try not to blow your mind with advanced statistics, okay? The title of the exam is PRINCIPLES of Statistics. If you can truly master the basic principles, you will be in a good place for the exam.

I don't know where you got that question from, but I really do think it is beyond the scope of this particular statistics exam.

Hope that helps,
Snazzlefrag