Math Help - College Statistics

1. Re: College Statistics

Now I keep getting 21.65064519 as my answer. This is what I did:

The integral from 5 to 6 of (x^2 - μx)/σ dx = (182-33μ)/6*σ

Plugging μ and σ into that, I then got the 21.65 above. I didn't get what you got.

2. Re: College Statistics

Originally Posted by AwesomeHedgehog
Now I keep getting 21.65064519 as my answer. This is what I did:

The integral from 5 to 6 of (x^2 - μx)/σ dx = (182-33μ)/6*σ

Plugging μ and σ into that, I then got the 21.65 above. I didn't get what you got.
no...

you don't know what the Normal distribution is? I don't see how you can be trying these problems without knowing that.

$\large N(\mu,\sigma)=\dfrac{1}{\sqrt{2\pi}\sigma}e^{-\dfrac{(x-\mu)^2}{2\sigma^2}}$

and you can't just integrate it you have to look it up in a table or use software or something. You didn't go over any of this in class? It's not in your book at all?

3. Re: College Statistics

I know what the Normal distribution, I just thought you were talking about the standard normal.

What software did you use to integrate it?

4. Re: College Statistics

Originally Posted by AwesomeHedgehog
I know what the Normal distribution, I just thought you were talking about the standard normal.

What software did you use to integrate it?
wolfram.com will work use

1-CDF[NormalDistribution[$\mu,\sigma$],5]

5. Re: College Statistics

Alright, I got the same answer that you got with that. Thank you.

Now, for part (d) it asks what happens to the probability as n increases and I want to say that the probability will decrease.

6. Re: College Statistics

Originally Posted by AwesomeHedgehog
Alright, I got the same answer that you got with that. Thank you.

Now, for part (d) it asks what happens to the probability as n increases and I want to say that the probability will decrease.
yes

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