Probability and Statistics Calc Based

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Homework Statement


that it is exact...
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X and Y are discrete random variables with joint pmf

Chart attached
Capture.PNG



(a) Find V ar(X) and Var(Y).
(b) Find Cov(X; Y).
(c) Find the correlation of X and Y.
(d) Find the conditional distribution of X given that Y= 3

Homework Equations



Trying to check my answers to see if i am correct.


The Attempt at a Solution


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a. Var(x) = 0.8 Var(Y) = 1
b. 0.4
c. 0.1414
d. 1/5;1/5;3/5

Thanks
 
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Dr. Courtney said:
What is pmf?
probability mass function
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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