STAB22H3 Lecture 19: STAB22-Lecture 19-Continuation of CH. 14
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Combining values of random variable: example problem, 3 coins. Probability: here"s a random variable, called x: Find the standard deviation of x variance: example problem: x. 1: formula: var(x) = (x- x )2 x p(x, mean = 0(0. 5) + 1(0. 5) = 0. 5. P x- (x- x )2 (x- x )2 x p(x) 0. 25: var(x) = 0. 125 + 0. 125 = 0. 250, standard deviation of x = square root of 0. 250 = 0. 5. Multiply it by b: take all the values and change them, while leaving the probabilities alone, here"s y, with mean 4 and sd of 0. 45. 2y would look like this, the mean would be 8 and sd would be 0. 9. 0. 1: y +3 would look like this: If you add a constant to a random variable, what happens to its mean and standard deviation: mean of (x+a) = e(x+ a) = e(x) + a.
