Chapter 15: Random Variables

Question 1

Random Variables

Answer 1

Numerical outcomes of random behavior

Question 2

Discrete Random Variable

Answer 2

Can only take on a countable number of values

Question 3

Continuous Random Variable

Answer 3

Can take on an infinite number of values in an interval on a number line

Question 4

Probability Distribution

Answer 4

A display of the entire set of values with associated probability

Question 5

Multiplying Or Dividing Random Variables By A Constant c

Answer 5

1. μ multiply/divide by c
2. σ multiply/divide by c
3. Shape remains the same
4. σ^2 (Variance) multiply/divide by c^2

Question 6

Adding Or Subtracting Random Variables By A Constant c

Answer 6

1. Mean or median add/subtract by c
2. Spread/variability remains the same
3. Shape remains the same

Question 7

Adding Or Subtracting Random Variables

Answer 7

Z=X+Y:
1. μZ=μX+μY
2. σZ=squareroot[(σX)^2+(σY)^2]

Z=X-Y:
1. μZ=μX-μY
2. σZ=squareroot[(σX)^2+(σY)^2]

Question 8

Linear Combinations

Answer 8

For any two random variables X and Y, and real numbers a and b, the expression aX+bY is called a linear combination of X and Y
Mean=aμX+bμY
Standard Deviation: squareroot{[a^2(σX)^2]+[b^2(σY)^2]}