Probability Models

6.2

Vocabulary

• Sample space – S, set of all possible outcomes• Event – outcome or set of outcomes of a

random phenomenon. A subset of the sample space

• Probability Model – mathematical description of a random phenomenon consisting of the sample space S and a way of assigning probabilities to events

Tree Diagram

Multiplication Rule

• If you can do one task in a number of ways and a second task in b number of ways, then both tasks can be done in a x b number of ways.

Replacement

• With replacement:

• Without replacement:

Sample Space

• Define the sample a) Choose a student in your class at random. Ask how much time

they spent studying during the past 24 hours b) The Physician’s Health Study asked 11,000 physicians to take an

aspirin every other day and observed how many of them had a heart attack in a five-year period.

c) In a test of a new package design, you drop a carton of a dozen eggs from a height of 1 foot and count the number of broken eggs.

d) A nutrition researcher feeds a new diet to a young male white rat. The response variable is the weight (in grams) that the rat gains in 8 weeks

e) Choose a student in your class at random. Ask how much cash they are carrying