Ch. 5.1 (Random Variables)

Question 1

Random Variable

Answer 1

Associates a numerical value with each outcome of an experiment

Question 2

Discrete

Answer 2

Has a finite number of allowed variables

• number of Skittles in a package
• number of face cards in 10 draws

Question 3

Continuous

Answer 3

Has an infinite number of allowed values (can take on any value throughout an interval of numbers)

• height
• time

Question 4

Probability Distribution

Answer 4

A description that gives a probability for each value of the random variable. Often expressed as a table, formula, or graph.

Requirements:

• has a numerical random value (RV)
• the sum of p(x) adds up to 1
• p(x) is between 0 and 1

Question 5

Expected Value

Answer 5

The mean of X

(RV • p(x)) + (RV • p(x)) + …

Question 6

Variance

Answer 6

The mean of the squared deviations (the mean of the random variable)

(X - U) ^2

*standard deviation = square root of variance