Thread: Continuous probability function

1. Continuous probability function

Hi there everyone! Long time lurker first time poster. I'm at the end of my last class for the semester and we have this last assignment but the teacher has put it online for all of us to learn by ourselves. I am terrible learning this way so maybe someone here can help? =)

We're given a function, in this case it is f(x) = 1.4x

the problem says that it is a PDF over the interval 1 (less than or equal to) x (less than or equal to) c. It asks us to find c with a 3 decimal place value. I figured out how to do the same type of problem with the integral 0 < x < c but this stumps me, help anyone? Thanks in advance!

2. Originally Posted by adepascale
Hi there everyone! Long time lurker first time poster. I'm at the end of my last class for the semester and we have this last assignment but the teacher has put it online for all of us to learn by ourselves. I am terrible learning this way so maybe someone here can help? =)

We're given a function, in this case it is f(x) = 1.4x

the problem says that it is a PDF over the interval 1 (less than or equal to) x (less than or equal to) c. It asks us to find c with a 3 decimal place value. I figured out how to do the same type of problem with the integral 0 < x < c but this stumps me, help anyone? Thanks in advance!
You haven't given enough information.

What is the probability?

Once you have the probability, call it P, you evaluate

$\displaystyle P = \int_{1}^{c}{1.4x\,dx}$ and then solve for c.

3. That is literally the question typed out verbatum, should I e-mail the instructor and ask for more information?

4. Originally Posted by adepascale
That is literally the question typed out verbatum, should I e-mail the instructor and ask for more information?
Yes

5. He said that the probability has to add up to 1... but i'm still not sure how I would go about evaluating it

6. Originally Posted by Prove It
You haven't given enough information.

What is the probability?

Once you have the probability, call it P, you evaluate

$\displaystyle P = \int_{1}^{c}{1.4x\,dx}$ and then solve for c.
P = 1 by definition.

7. Originally Posted by adepascale
He said that the probability has to add up to 1... but i'm still not sure how I would go about evaluating it
Do the integral. Equate it to 1. Solve for c.