# How to get this number?

#### Aauusteja

##### New Member

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)=....

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#### SmoothJohn

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

John

#### Dason

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

#### SmoothJohn

##### New Member
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?

#### Aauusteja

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

#### Aauusteja

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

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#### SmoothJohn

##### New Member
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.

#### Aauusteja

##### New Member
Thanks, you realy helped me. :tup:
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)

#### SmoothJohn

##### New Member
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?

#### Aauusteja

##### New Member
It's all, nothing isn't missing. :yup:

#### Aauusteja

##### New Member
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?