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Part V: Statistical Studies and the Hunt for a Meaningful Relationship
Organizing a Two-Way Table
To explore links between two categorical variables, you first need to organize
the data that’s been collected, and a table is a great way to do that. A two-way
table classifies individuals into groups based on the outcomes of two categor-
ical variables (for example, gender and opinion).
Suppose your local community developers are building a campground, and
they’ve decided pets will be allowed as long as they’re on a leash. They are
now trying to decide whether the campground should have a separate sec-
tion for pets. You have a hunch that non–pet campers in the area may be
more in favor of a separate pet area than pet campers, so you decide to find
out what the members of the camping community think. You randomly select
100 campers from the local area and conduct a pet camping survey, record-
ing each person’s opinion on having a pet section (yes, no) and if they camp
with pets (yes, no). You now have a spreadsheet with 100 rows of data, one
for each person you surveyed. Each row has two pieces of data: one column
for whether the person is a pet camper (yes, no) and one column for that
person’s opinion on having a pet section (support, oppose). Suppose the first
10 rows of your data set look like what’s shown in Table 19-1.
Table 19-1 First 10 Rows of Data from the Pet Camping Survey
Person Pet Camper? Opinion on a Separate Pet Section
1 Yes Oppose
2 Yes Oppose
3 Yes Support
4 No Support
5 No Support
6 Yes Support
7 No Oppose
8 No Support
9 Yes Support
10 No Oppose
From this small portion of your data set, you can start to break it down your-
self. For example, looking at column 2 results, you see that half the respon-
dents (5 ÷ 10 = 0.50) camp with pets and the other half do not. Of those who
camp with pets (that is, of those five people who have a yes in column 2),
three of them (60%) support having a separate section; and the same results
are true for non–pet campers. These results from these 10 campers likely

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