c:ma:2019:multiple_regression_exercise
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Table of Contents
Class Activities
Ex. 1
- Install packages ISLR
- use a dataset, Carseats
- Build regression models with a DV, sales and IVs, your choices
- Use
?Carseats
command for the explanation of the dataset - Use
str
function to see the characteristic of each variable. Make it sure thatSelvesLoc
variable should be factor, not int or anything. - 변인설명을 토대로 가설만들기
- 종속변인 = Sales
- 독립변인 = 숫자변인 1 + 종류변인 1 (조별 선택)
- Multiple regression without interactin
- Multiple regression with interaction
- 가설 만들기
- 종속변인 Sales
- 독립변인 여러개 (interaction 없이)
- Modeling 해 볼 것
see hierarchical regression
see also statistical regression methods ← 많이 쓰이지 않음
Make a full model (with all variables) then reduce down the model until you find it fitted.Make a null model (with no variables) then, build up the model with additional IVs until you find a fitted model.Can we usestep
orstepAIC
(MASS package needed) function?Interpret the result
> step(lm.full, direction=“back”)
Ex. 2
- Install packages tidyverse
- load the tidyverse
install.packages("car")
data("Salaries", package = "car")
- Use a dataset Salaries
- describe the data set
—-
- Regress sex variable on salary variable
- Write the regression model
- Discuss the difference
- Use rank variable for the same purpose
- –
- Use yrs.service + rank + discipline + sex
- on salary
- How do you interpret the result?
—–
위의 Salaries 데이터사용이 안 될 때
- download to R from here salaries.csv
- use to import the data set.
Salaries <- read.csv("http://commres.net/wiki/_media/salaries.csv")
- for information about Salaries (it may not be loaded),
- use
??Salaries
to describe the data set.
—–
Please copy and paste the proper r command and output to a txt file (use notepad or some other text editing program). You could use MS Word, but, please make it sure that you use type-setting fonts such as “Courier New.” The below output, as an example, includes the r command head(Salaries)
and the output.
<code>
Discussion
Common topics
- What affects students GPA? Or what determines students' GPA?
Group topics
Making Questionnaire
Questions you submit at the ajoubb.
Then we will list questions in Google docs Google survey
c/ma/2019/multiple_regression_exercise.1636454029.txt.gz · Last modified: 2021/11/09 19:33 by hkimscil