1. Determining Whether There Is an Association
Making a Two-Way Table
Taken from Explorations Workbook Pg 351
A poll of 120 town residents found that 40% own a bike. Of those who own a bike, 75% shop at the town’s farmer’s market. Of those who do not own a bike, 25% shop at the town’s farmer’s market.
Here’s how to fill out THIS two-way table with the information that is given in THIS situation.
Start at the bottom right corner. Fill in the total.
Fill in right column. 40% of those polled own a bike, so
40% of 120 is ____
Fill in top row. 75% of those who own a bike shop at the market, so
75% of ____ is ____
Fill in the second row. 25% of those who own a bike also shop at the market 25% of ____ is ____
Fill in the last row.
Double check!
What percent of all the residents
polled shop at the farmer’s market?
Determining Whether There Is an Association
Taken from Explorations Workbook Pg 352
One hundred teens were polled about whether they are required to do chores and whether they have a curfew. Is there an association between having a curfew and having to do chores?
Find the relative frequency of having to do chores.
Total who have to do chores  _____
Total number of teens polled 
Find the relative frequency of having to do chores among those who have a curfew.
Number with a curfew who have to do chores  ____
Total number with a curfew 
curfew
Compare the relative frequencies. Students who have a are less likely / more likely to have to do chores than the general population.
Is there an association between having a curfew and having to do chores? Explain.