FAQ: Associations: Two Categorical Variables - Expected Contingency Tables

This community-built FAQ covers the “Expected Contingency Tables” exercise from the lesson “Associations: Two Categorical Variables”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Master Statistics with Python

FAQs on the exercise Expected Contingency Tables

There are currently no frequently asked questions associated with this exercise – that’s where you come in! You can contribute to this section by offering your own questions, answers, or clarifications on this exercise. Ask or answer a question by clicking reply (reply) below.

If you’ve had an “aha” moment about the concepts, formatting, syntax, or anything else with this exercise, consider sharing those insights! Teaching others and answering their questions is one of the best ways to learn and stay sharp.

Join the Discussion. Help a fellow learner on their journey.

Ask or answer a question about this exercise by clicking reply (reply) below!
You can also find further discussion and get answers to your questions over in Language Help.

Agree with a comment or answer? Like (like) to up-vote the contribution!

Need broader help or resources? Head to Language Help and Tips and Resources. If you are wanting feedback or inspiration for a project, check out Projects.

Looking for motivation to keep learning? Join our wider discussions in Community

Learn more about how to use this guide.

Found a bug? Report it online, or post in Bug Reporting

Have a question about your account or billing? Reach out to our customer support team!

None of the above? Find out where to ask other questions here!

This is not very clear. In the guidance it says, " if there were no association between the leader and influence questions, we would expect 2087 people to answer no to both… The more that the expected and observed tables differ, the more sure we can be that the variables are associated. In this example, we see some pretty big differences (eg., 3015 in the observed table compared to 2087 in the expected table). This provides additional evidence that these variables are associated.

In our observed and expected tables,
observed contingency table:
authority no yes
special
no 4069 1905
yes 2229 2894
[[3390. 2584.]
[2908. 2215.]]

Well 4069 is bigger than 3390? Likewise 2894 and 2215. But it’s printed “expected contingency table (no association):”)

What am I not getting?

Maybe you are over thining this…

The expected is a hypothetical number that shows the frequencies of responses that you would get if the two categorical values are not correlated in any way.

Looking at the values we actually got (the first part of exercise, ie the responses of a real survey), we notice they are different, (it does not matter if they are bigger or smaller) it just means that its likely that our categorical values have a correlation… be it positive or negative, that is for us to work out if we wanted to…

Hope that helps…

1 Like

I think you did the order wrong on your statement. The output should look like:

observed contingency table:
authority    no   yes
special              
no         4069  1905
yes        2229  2894
expected contingency table (no association):
[[3390. 2584.]
 [2908. 2215.]]

The top specifies what we got and the bottom (expected) output is the values we would have expected if there was no association. It is not stating that there is no association.

There is an assocation.

2 Likes