LM 03

Question 1

Random Variable

Answer 1

An assignment if numbers ti outcomes in some sample space.

Question 2

Fill in the blank: A data set has —- and ——.

Answer 2

Mean and variance

Question 3

Fill in the blank: A random variable has —— and ——-

Answer 3

Expected value (similar to mean) and variance

Question 4

Expected Value of a Random Variable

Answer 4

E(x) = xP(x=x1) + x2P(x=x2) … xnP(x=xn)

Question 5

How is expected value denoted

Answer 5

E(x) or mu

Question 6

Variance of RV formula

Answer 6

VAR(x) = (x1-u)^2 * P(x=1) + (x2-u)^2 * P(x=2) +…+ (xn-u)^2 * P(x=xn)

Where u is the expected value, also E(x)

Question 7

How is variance denoted

Answer 7

Var(x) or sigma^2 (o^2)

Question 8

How is standard deviation denoted

Answer 8

SD(x) or sigma (o)

Question 9

Dependent Events P(AnB) =

Answer 9

P(B)* P(A|B)

Question 10

Independent Events P(AnB) =

Answer 10

P(B) * P(A)

Question 11

Two independent variables X and Y
Var(X+Y) =

Answer 11

Var(x) + var(y)