For random variables X a.nd Y vvith joint P 11:F Px,Y(:i;, y) given in Exarr1ple 7.11 , vvrit e a MATLAB function xy=dtrianglerv (m) th at generates rn, sample pairs.
Lecture 7 Nicole Rubenstein September 19, 2017 6 Notes on topics from last lecture 2 2 2 Say we have Y = aX + b;E[X] = ▯;V ar(X) = ▯ . Then we know E[Y ] = a▯ + b and V ar(Y ) = a ▯ . Another way to compute variance: 2 2 V ar(X) = E(X ) ▯ [E(X)] 2 2 2 Here, E(X ) is the second moment of X and [E(X)] is the mean squared. If you can compute E(X ), this is typically a much easier way to ▯nd the variance. Proof.