Let X and Y be the coordinates of a point chosen uniformly at random from the triangle that joins the points (0,1), (0,0), and (1,0).

1) Find the joint distribution of X and Y.

2) Determine the expected value of X and the expected value of Y (these are the expected coordinates of a point chosen at random).

3) Find the correlation between X and Y.

4) If the original units were measured in inches, would there be a different correlation if the units were changed to centimeters? Justify your answer mathematically?

For 1, I gotfX,Y(x,y)=2 and 2 I gotfX(x)=2−2yandfY(y)=2−2x. Then for correlation in 3 I got 112−(4−4x−4y+4xy). I feel like I am forgetting something however and this should be different. For 4, I know this is unchanged but I am not sure how to show this. Any help is appreciated.