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Course: AP®︎/College Statistics > Unit 1
Lesson 3: Representing two categorical variables- Two-way frequency tables and Venn diagrams
- Read two-way frequency tables
- Create two-way frequency tables
- Two-way relative frequency tables
- Analyze two-way frequency tables
- Interpreting two-way tables
- Interpret two-way tables
- Mosaic plots and segmented bar charts
- Analyzing mosaic plots
- Mosaic plots
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Analyzing mosaic plots
We can use mosaic plots to draw conclusions about relationships between two categorical variables. Created by Sal Khan.
Video transcript
- [Instructor] We're told that
administrators at a school are considering a policy change. They survey a group of
students, staff members, and parents about
whether or not they agree with the new policy. The following mosaic plot
summarizes their results. Which of the following
statements can we justify from the mosaic plot? So pause this video and try to
figure this out on your own. Pick which of these
statements can be justified and there could be more than
one based on this mosaic plot. All right, now let's work
through this together. So before I even look at the choices, let me see if I can interpret this. So this mosaic plot, what it does above and
beyond a segmented bar chart, is it gives us the width
that shows us how many, for example, students
versus staff versus parents were sampled or surveyed. And it looks like more than half of the people surveyed were students. And then staff and parents seem similar. In terms of who is
agreeing with the policy, so that's that light blue color. It seems like students are
not very likely to agree with the policy. It looks like staff is very
likely to agree with the policy, that the bulk of staff
is agreeing with it. And parents are kind of on both sides. So let's see which of these
statements are consistent with what we just looked at. Parents were the least likely
to agree with the new policy. No, that's not true. The least likely to
agree with the new policy that's students, right over here. They were definitely the least likely. The lowest percentage of students are agreeing with the policy. So I don't like that choice. More than half of the total
responses came from students. And that does look like the case. 'Cause if you view this entire
width as the total responses, it looks like the student
width right over here, that is more than half of it. It looks like it's about
50 something percent or even 60 percent. So I like this choice right over here. And then last but not least, there were more total "No"
responses from students than from staff and parents combined. So let's look at the no
responses from students. No, that's that darker blue color. The no responses for students
is this area right over here. And then the nos, so I can,
maybe I'll shade all of that in, and then the no responses from staff and parents combined, that
is this area right over here. And it does look like indeed
the total no responses from students, this area is much larger than this area right over here. So I like this choice as well.