Need help finding the Variance

T

thelazyman

Junior Member
Joined
Jan 14, 2006
Messages
58
Hi I was given this

Y 1 2 3
1 0.03 0.06 0.06
2 0.02 0.04 0.04
3 0.09 0.18 0.18
4 0,06 0.12 0.12



The X's are the values 1,2,3 for the top row. It says to calculate the Var (X) and var (y). I tried calculating this to no avail. I tried to find the initial mean of the first row of 1, which would be 0.2/4 = 0.05, then did the squaring and calculated all the sums, the answer is var(x) = 0.56, but i dont know how they got that, any help would be great!!!. Thanks!!
 
A little better description might help. Exactly what did the problem statement say?
 
I kind of made a note of that, u need to find var x and var y, i gave the input data, i tried to find it to no avail.
 
thelazyman said:
Code: 
Y	  1	   2	   3
1	0.03	0.06	0.06
2	0.02	0.04	0.04
3	0.09	0.18	0.18
4	0,06	0.12	0.12

The X's are the values 1,2,3 for the top row.

I'm not sure what this statement is supposed to mean.
Click to expand...

thelazyman said:
I kind of made a note

We need an explanation more detailed than "kind of". 8-)

i gave the input data

Well, I see the array, but I'm not sure what the data is for var(X).

Is the array format your idea, or did you type row and columns because that's how it appears in your materials?

I see different interpretations.

There could be three separate exercises for var(X) and four separate exericses for var(Y).

Maybe X_1 = 1, X_2 = 2, and X_3 = 3, and the numbers 0.03, 0.06, 0.06 could be values of p(X_i). That interpretation would be four distinct exercises for var(X).

Population variance ?

Sample variance ?

Discrete sets ?

I dunno what you're actually expected to do.
Click to expand...

If you are not able to share with us all of the given information as you've received it, then perhaps you could try the following two steps.

(1) Explicitly list the elements of set X, for which they claim var(X) = 0.56

(2) Show us the formula that you're supposed to use for variance, including symbol definitions

PS: The symbols X and x do not mean the same thing. I'm assuming that X is the name of a set.
 
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