# Questions tagged [categorical-data]

Categorical (also called nominal) data can take on a limited number of possible values called categories. Categorical values "label", they do not "measure". Please use [ordinal-data] tag for discrete but ordered data types.

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15 views

### Is a threshold for categorical variables necessary in GLM?

I was wondering if there is a specific guideline or rule of thumb somewhere regarding the use of categorical predictor levels with low representation in the dataset? I have a few categorical ...
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### Use of SEM in case of categorical data like yes or no questions and continuous data like likert scale"

I am doing research on school effectiveness. i have to see the effect of different variables on school effectivenesss. Teacher related variables: Teacher competence ...
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### Categorical features in a random forest

I am currently training a random forest. After transforming a categorical feature into dichotomous columns, should I drop the first level? For example, I have three unique values in a featured named <...
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### Problem with dimension reduction using pca

Im measuring the concept of group centeredness through 4 dimensions. Of these 4 dimensions i have 2-3 statements. I have a small numerus from the survey. Im running pca for each of these dimensions ...
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### Which test to use for paired samples with different sizes and only 1 categorical variable?

I am testing 9 rooms for bacteria growth, and want to see affects of heat. Assume Blue Room is colder, Red room is warmer. I am not sure how to approach this because samples are too small (so can't ...
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### How to find “dependency” between categorical variables and the dependent variable, also categorical

Please edit the title if the wording is incorrect Imagine to have a dataset of recipes that works like this: each row is a recipe, where the ingredients are predictors and the dependent variable ...
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### How to find out if interaction of three binary variables is significant?

If I have two binary explanatory variables $A$ and $B$, and one binary response variable $C$- we can find out if $C$ is associated with $A$ or $B$ by creating contingency tables of $A,C$ or $B,C$ and ...
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### Isometric log-ratio transformatio in Python [closed]

I want to transform my categorical data with ILR transformation, and later transform it back with the inverse. In R there are the functions ilr and invilr to simply do it. I can't find anything close ...
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### Regressing for Age in R Across Several Dependent Variables

I have been working on a large statistics project that for the majority of analyses, consists of fairly simple stats. However, I have been struggling with a more complex analysis and would really ...
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### Why or when to convert a semi disperesed numeric column to a categorical column?

This is an open ended WHY TO or WHEN TO question rather than a question on HOW TO encode numeric to categorical data. I am currently working on Telco Customer Churn dataset from Kaggle. This is a ...
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### Difference between CFA using WLSMV estimator and IRT

I am trying to understand the differences (or similarities) between conducting CFA on categorical data using the WLSMV estimator in SEM and item response theory analysis. I would appreciate any input. ...
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### Reference for Fisher's exact test for $r \times c$ tables?

I see that in R, there is an example of running Fisher's exact test (see ?fisher.test) with an $r \times c$ contingency table with $r, c > 2$. I could not find ...
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### Inter-rater agreement (raters >2) of non-random items

I ran a survey where participants (P) had to choose one category out of six (C1-C6) for each of five items. The data looks like this: ...
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### How to test similar distribution of categorical data (k=3) between 2 paired samples

I'm looking for a test to compare the distributions of categorical data (3 levels: J,N,P) between 2 dependent groups (paired samples: question_1, question_2). We have 85 participants, each one of ...
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### How to determine which columns make p-value result in 0.0 in contingency table?

I have a contingency table with which I am estimating if some categories are seasonal or not. I use p-value and Cramers V for that but for this question only p-value is important. The p-value resulted ...
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### Within group variation for categorical dependent variable

I need some help. I am trying to test within group variations but my situation seems a little bit more complex and I’m yet to find a statistical test that caters to this situation. Or perhaps I ...
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### Sensitivity test

I have an independent variable that has 3 groups - 'Yes' 'No' and 'Unknown'. I have decided that I can assume the 'Unknowns' as 'No'. I want to run sensitivity analysis to test whether making this ...
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### Boxplot on one one significant interaction of mixed effect model

I have a mixed effect model with two interactions statistically significant : one related to a continuous variable, the time of my experiment and one in relation to a categorical variable the day of ...
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### Data-preprocessing for a machine learning model

I am confused about how to preprocess range based category such as age, tumor-size & inv-nodes. Should I take an average of the limits, as in - 14.5, 24.5 and so on or do one hot encoding of the ...
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### Visualizing regression with categorical variables

I am working my way through linear models in matrix form using mainly Brown (2014) Linear Models in Matrix Form. The book presents a schematic representation of observed and fitted values in a linear ...
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### Probability of linear separation in a dataset with categorical response

I am simulating datasets to which I fit polytomous logistic regression models. The maximum likelihood estimator of this model is undefined when all categories are linearly separated (and it is quite ...
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### What kind of statistic test should i use?

I need some help to find the correct method for my hypothesis. The aim is to find out whether the use of a certain procedure (case A: none / case B: use of my artifact) influences the time factor of a ...
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### Can I use multiple Chi-Square tests and combine the results of the analyses or is there a better way to do this?

I have the results of a survey of employee satisfaction, where employees answer 20 questions as either "agree", "disagree", or "neutral". The questions are grouped into themes as follows: Q1-5: "...
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### Removing group effects from data

I have a set of data which consists of measurements from sensors for a machine. I know that depending on what the machine is doing at the time, that several different ranges of measurement data will ...
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### How Helmert Encoding is done here?

I was going through an article on Helmert Coding there I encountered an example in which I was not able to understand how Helmert coding is done. I went through How to calculate Helmert Coding this ...
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### Significance test for a discrete symmetric ordinal distribution

What are possible extensions to the binomial test for a multinomial distribution? Here is a concrete examples: let's say I have 5 positive and 10 negative outcomes with a one-sided test for the null ...
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### Logistic regression analysis after changing variables to factors [closed]

I have done a logistic regression with my binary outcome. Majority of my variables in my model were changed to factors as they are categorical. I put my categories into levels ie. Very Low = 1, Medium=...
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### Categorical Principal Components Analysis

I performed a Categorical Principal Components Analysis in ordinal data and I created 3 dimensions. Should I use the component loadings or the object scores, as my new 3 variables?
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### Visually, how strong would you rate the association between this nominal predictor variable and continuous response variable?

I've yet to find an easy-to-understand and easy-to-implement way to statistically model the strength of association between nominal data and continuous data. So I'm trying to get a rough idea visually ...
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### How to deal with 100+ levels in categorical variable in multiple linear regression? [duplicate]

Im trying to model: Y~x0+x1+x2+x3+x4, were Y is a continous variable (cost), x0 is the ...
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### How to examine the relationship between categorical variables with several levels?

I would like examine if the job satisfaction of part-time workers is higher or lower compared to full-time workers. My dataset consists of 4125 cross-sectional observations. independent variable: ...
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### Correlation between classes within categorical feature in a ML model

I have a dataset containing numerical and categorical features. Let's say I have one categorical feature C with classes c_0 ... c_n. I build a model that has some ...
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### How to deal with problems like this ? What machine learning algorithms should be used?

I am new to machine learning and this community too. So please pardon me if i make any mistake while putting up this question. I am trying this https://www.kaggle.com/doaaalsenani/usa-cers-dataset ...
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### How to use Cronbach's Alpha?

Is it appropriate to use Cronbach's Alpha for nominal variables? I have 20 nominal variables (two dimensions with 10 questions each) that ask about the characteristics of work performance. The ...
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### Help with understanding logistic regression's $R^2$ value

I have a set of ordinal varies (0,1,2,3,4) and I'm trying to do binary logistic regression with a dichotomous variable (0,1). These are the values, where the numerator is = 1 and the denominator is = (...
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### Multiple regression with mixed continuous/categorical variables: Dummy coding, scaling, regularization

I have a dataset, consisting of 4 continuous and 1 categorical (three levels) indepentend variable. On this dataset, I want to perform a multiple linear regression with a regularization (specifically ...