# Thread: How to get this number?

1. ## How to get this number?

a) Variant
P(x=0)=P(0,0)+P(0,1)+P(0,2)=0.27
P(x=1)=P(1,0)+P(1,1)+P(1,2)=0,4
P(x=2)=P(2,0)+P(2,1)+P(2,2)=0.33
expected value ( I do not know how to get this?)
E(x)=0,(27)+1,(4)+2(33)=....

2. ## Re: HOw to get this number?

Is something missing here? The top equation does add up correctly. There follows a bunch of white space an an unrelated calculation.

John

3. ## Re: HOw to get this number?

Yeah. You really don't specify what's giving you problems.

4. ## Re: HOw to get this number?

Originally Posted by Dason
Yeah. You really don't specify what's giving you problems.
I correct it...

5. ## Re: HOw to get this number?

Ok, I think I know what is confusing you. (In your initial post, you seemed troubled that your calculated expected value was greater than one. Is that the problem?)

After you calculate the expected value, what is it that you know? Or to put it another way, what does the expected value tell you?

6. ## Re: HOw to get this number?

I do not know how to calculate it ( how to find) expected value.

7. ## Re: How to get this number?

Noone do not want to help...

9. ## Re: How to get this number?

E(x)=0,(27)+1,(4)+2,(33)=27/99+13/9+21/9=401/99
It's okay?

10. ## Re: How to get this number?

Your notation indicates that you are mixing up two systems. I'll write my answer in the North American English fashion.

E(x)=0*(0.27)+1*(0.4)+2*(0.33)=1.06

The idea is that you expect to have 0 sales 27% of the time, 1 sale 40% of the time and 2 sales 33% of the time. For a randomly selected period, you expect 1.06 sales.

11. ## Re: How to get this number?

Thanks, you realy helped me.
But one more question
Define the chance variable H as the total sales on markets X and Y
How that will look?
P(x,y)=P(1,1)+P(1,2)+P(2,1)+P(2,2)

12. ## Re: How to get this number?

That isn't a question; it's telling you what H stands for.

Now that I look again, is the posted table complete? or is some information missing?

13. ## Re: How to get this number?

It's all, nothing isn't missing.

14. ## Re: How to get this number?

If I good understand
I need to define H e.g all goods sould be sold
So P(x,y)=P(1,1)+P(1,2)+P(2,1)+P(2,2) Can be like this?

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