q12 Suppose X is a random variable with mean 10 and variance 25.

Suppose Y is a random variable with mean 20 and variance 9.

X and Y are independent.

What is the standard deviation of the difference X - Y?

16

square root of 34

4

34

q13 Suppose X is continuous with f(x) = 3/8 x^2 from 0 to 2. What are the values of P(X=1) and f(1)?

0 and 3/8

0, 0

None of the other choices is correct

3/8 and 0

3/8 and 3/8

just need answer