10

Question 1

Variance is equal to the expected value of what?

Answer 1

E[(x - mu)^2]

Question 2

Expected value of X: E(X = n)?

Answer 2

x_1 p(x_1) + x_2 p(x_2)… x_n p(x_n)

Question 3

The units of standard deviation is the same as?

Answer 3

Original units of measure

Question 4

The variance and standard deviation tell you what about the random variable?

Answer 4

How repeatable, similar, and consistent a random variable is.

Question 5

Range of random variance X?

Answer 5

Largest and smallest possible X value as it tells you something about the difference.

Question 6

Inter-quartile range?

Answer 6

Length of the interval that captures the center 100(beta - alpha)% of random variables distribution (Q_beta - Q_alpha)

Question 7

Linear transformation really does what?

Answer 7

Change units

Question 8

Linear transformation to create a new random variable?

Answer 8

Y = aX + b

Question 9

If a != +-1, then the variance and sd will?

Answer 9

Change.

Question 10

if given two random variables, X and Y, with each having their own means and variance. Then?

Answer 10

a new random variable R = X +- Y can be created

Question 11

Covariance of random variables X and Y is?

Answer 11

Tells you something about what X and Y do together on average.

Question 12

If you have a new random variable that is the sum of two random variables, what happens with its means?

Answer 12

You add their means of the two random variables to get the mean of the new random variable.

Question 13

If you have a new random variable that is equal to the total of two random variables, what happens with the variance?

Answer 13

The sum of the variances of the two random variables in addition to the sum of the Covariance*2.