8 2 Relative Frequency Objective The students will

8 -2 Relative Frequency Objective: The students will take notes on how to Construct and interpret two-way frequency tables. Students will demonstrate their understanding by achieving an accuracy rate of 70% or higher on my. hrw. com assignment tomorrow. Standard: Math Notebook CFU: What are we going to learn TODAY? © 2012 Data. WORKS Educational Research EDI Lesson Plan Template for TEACHER-CREATED lessons.

8 -2 Relative Frequency Conditional Relative Frequency: Frequency Examine relationships between categorical variables. It describes what portion of a group with a given characteristic also has another characteristic. Ex. What is the conditional relative frequency that a student likes to lift weights, given that the student does not like aerobics?

8 -2 Relative Frequency Marginal Relative Frequency: Frequency Describes what percent of totals has a given single characteristic. Ex. What is the marginal relative frequency of students surveyed who like weight lifting? Not like

8 -2 Relative Frequency Joint Relative Frequency : - the number of times a combination of two conditions occurs. Ex. Find the joint relative frequency of students surveyed who like aerobics exercise but dislike weight lifting.

8 -2 Relative Frequency Example 1: Finding Joint and Marginal Relative Frequencies The table shows the results of randomly selected car insurance quotes for 125 cars made by an insurance company in one week. Make a table of the joint and marginal relative frequencies. Teen 0 acc. 1 acc. 2 + acc. Total Adult Total

8 -2 Relative Frequency Example 2: Using Conditional Relative Frequency to Find Probability A reporter asked 150 voters if they plan to vote in favor of a new library and a new arena. The table shows the results. Make a table of the joint and marginal relative frequencies. Library Arena Yes No Total If you are given that a voter plans to vote no to the new library, what is the probability the voter also plans to say no to the new arena?

8 -2 Relative Frequency Example 3: Comparing Conditional Probabilities A company sells items in a store, online, and through a catalog. A manager recorded whether or not the 50 sales made one day were paid for with a gift card. Gift Another TOTAL Card Method Store Online Catalog TOTAL Use conditional probabilities to determine for which method a customer is most likely to pay with a gift card.

8 -2 Relative Frequency Example 4 Continued Gift Card Store Online Catalog TOTAL 0. 12 0. 18 0. 10 0. 40 Another Method 0. 18 0. 26 0. 16 0. 60 TOTAL 0. 30 0. 44 0. 26 1 P(gift card if in store) = 0. 4 P(gift card if online) ≈ 0. 41 P(gift card if by catalog) ≈ 0. 38 so most likely if buying online. A customer is most likely to pay with a gift card if buying online.