Summary
Summary Research Methods - Data Analysis I
- Course
- Institution
Summary of 1 pages for the course Research Methods In Psychology at UT
[Show more]
Seller
Followkayleighdebruin1
Reviews received
Content preview
RM | Unit 220 - Dummy coding with more than two categoriesBook: Analysing data using linear models
Chapter 6: 6.6, 6.7
Chapter 6.6: Dummy coding for more than two groups
Take for instance a variable Country, where in your data set, there are three different values for this
variable, for instance, Norway, Sweden and Finland, or Zimbabwe, Congo and South-Africa. Let’s call
these countries A, B and C. We can code this Country variable with three categories into two dummy
variables in the following way. First, we create a variable countryA. This is a dummy variable, or
indicator variable, that indicates whether a person comes from country A or not. Those persons that do are
coded 1, and those that do not are coded 0. Next, we create a dummy variable countryB that indicates
whether or not a person comes from country B. Again, persons that do are coded 1, and those that do not
are coded 0.
Note that we have now for every value of Country (A, B, or C) a unique combination of the
variables countryA and countryB. All persons from country A have a 1 for countryA and a 0 for
countryB; all those from country B have a 0 for countryA and a 1 for countryB, and all those from
country C have a 0 for countryA and a 0 for countryB. Therefore a third dummy variable countryC 197 is
not necessary (i.e., is redundant): the two dummy variables give us all the country information we need.
Chapter 6.7: Analysing categorical predictor variables in R
Check chapter in the book
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller kayleighdebruin1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.21. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
52510 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now