Linked Questions

4 votes
1 answer
2k views

Building separate logistic regression models for each categorical variable? [duplicate]

I am building a binary logistic regression model. I am not sure if using the variables as interactions is a better choice than building separate models for level of a categorical variable. Is there a ...
  • 43
0 votes
0 answers
287 views

R lm difference between interactions with category and one models per category [duplicate]

I am analysing a dataset of the performance of several species given an environmental variable. To do so, I use a simple linear model with the lm function from the stats package. Model 1 ...
3 votes
2 answers
66 views

Apply model for each variable or leave them as factor? [duplicate]

Imagine you want to predict ice-cream stock in your factory (by flavor). You have data like this: Which makes more sense / is better? Make flavor a factor and train the whole dataset Group by flavor ...
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1 vote
0 answers
34 views

How to treat apples and oranges best in multiple regression analysis? One fits all regression model or separate sub models? [duplicate]

I have a data set ready for multiple regression analysis that consist of apples and oranges. Let's say the depended variable is fruit size and there is a bunch of independent variables (categorical &...
0 votes
0 answers
21 views

Is it okay to run multiple regressions for each level of a predictor? [duplicate]

Suppose I want to test the effect of stress on the amount of uttered insults in three groups (psychologists, doctors and lawyers). The most direct thing that I can come up with would be a Poisson ...
14 votes
3 answers
14k views

Joint model with interaction terms vs. separate regressions for a group comparison

After gathering valuable feedback from previous questions and discussions, I have came up with the following question: Suppose that the goal is to detect effect differences across two groups, male vs. ...
  • 375
2 votes
1 answer
2k views

Comparison of Box-Cox transformed data with different lambdas

I'm trying to compare some data and see if there is a significant Pinteraction value between them. The data is highly skewed and thus I would like to use a transformation; a log transformation results ...
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3 votes
1 answer
535 views

Splitting dataset with respect to categorical variable

Assume that we have a data set with some features and a goal is to perform a classification. Let's assume that a dataset is moderately large compare to the total number of features. Next, assume that ...
  • 386
2 votes
2 answers
107 views

How do Regression Models Handle Categorical Variables?

How do Regression Models Handle Categorical Variables? At the end of the day, can categorical variables only be used to create "cohorts" within your data - and regression models are then fit ...
  • 6,916
1 vote
1 answer
436 views

Is there a benefit to splitting the data by gender or age range when building predictive models?

Assume we had a set of data that contained thousands of samples with the following information: gender, age, height, weight, country. Now, suppose we wanted to build a model for predicting people's ...
1 vote
2 answers
182 views

How to interpret MANOVA results after adding gender, splitting the file?

I am analyzing my 2x3 between subject design with MANOVA in SPSS at the moment. In the main model, there is 2 IV's and 2 DV's. Result of the test is 1 main effect and no interaction effect. In an ...
0 votes
1 answer
345 views

sub sample versus indicator variables (multiple regression)

In my study I have an continuous dependent variable (return) regressed on an independent continuous variable x1 (momentum) and a number of control variables. I am currently investigating whether this ...
0 votes
1 answer
313 views

Ordinal Regression with Categorical Predictors in R (Proportional Odds Logistic Regression)

My independent variable is Party Identification which I think will be best to create dummy variables for (Conservative, Labour) and then Lib Dem would be the intercept if I'm not mistaken. The ...
  • 1
0 votes
1 answer
154 views

How to test if the difference in the value of the coefficient of X is different between subgroups in R?

I have a simple linear model (earnings ~ age), and I want to test if the coefficient on age is significantly different for separate subgroups in my data (those with a bachelor's degree, and those ...
user avatar
2 votes
0 answers
157 views

why use dummy variable? If just focusing one specific group, can I avoid dummy and shrinking the dataset?

I am thinking about this question in using a dummy variable, from the textbook we know dummy play as a "switch" to represent different groups regression models. However, in data analysis, if ...
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