Tagged Questions

0
votes
0answers
12 views

Reduce Sample Size (Categorise??) [duplicate]

I have been looking for an answer to my question but havn't been able to find any literature documentation or help in regards. I have a large dataset which I need to further analyse. Because of this I ...
3
votes
1answer
100 views

Dummy coding for contrasts: 0,1 vs. 1,-1

I'm seeking your help in understanding the difference between two different contrasts for dichotomous variables. On this page: http://www.psychstat.missouristate.edu/multibook/mlt08.htm under ...
0
votes
0answers
42 views

ARIMA forecasting with external regressors

I am trying to build ARMAX models using auto.arima. I have a time series to forecast (weekly and monthly seasonality, I've put the ts() frequency=7), another two time series as external regressors, ...
2
votes
1answer
115 views
+100

Select best set of binary variables for clustering known sample labels

I have a set of samples, for which I know the "true groups". For this samples I have about 200 binary variables, I would like to know a method to select the subset of variables, that gives me a ...
3
votes
0answers
53 views

Variable selection / Dataset reduction for large datasets (in R)

I'm working on a behavoural scorecard modelling exercise, and many of the decisions taken to date have been based on the experience of a consulting credit analyst (whose experience software-wise is ...
1
vote
1answer
39 views

ARIMA and external regressors in SAS and R

So I remember reading somewhere that when we have external regressors, auto.arima cannot make correct predictions for the order of difference for either ...
2
votes
0answers
38 views

Dummy variables for time series

I'm a new user on R. I'm stuck on my times series research currently with the some questions. Not sure anyone can help me. Dummy variable. I wanted to add more than 1 dummy variable in the model. ...
0
votes
0answers
25 views

Plot normal probability for effect estimates in factorial design in R

I have 2 level Design (DOE) with 4 factors (A,B,C,D). I've already calculated the estimates for each main effect and all the interaction effects. How can I construct the normal probability plot to ...
0
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0answers
23 views

Setting indicator variables to equal 1 or 0 [migrated]

I have to set HIGPA to equal 1 if the gpa is greater than 3, and if it is less, then HIGPA must equal 0. I am using R. gpa is already a variable in the data. HIGPA is not. So far I have made HIGPA a ...
1
vote
0answers
19 views

Reference Group for dummy coding [migrated]

Is there any way to explicitly specify which group to take as reference group for dummy coding when modeling with lm function in R using categorical variables??
1
vote
1answer
42 views

Dealing with Dates of Birth in Predictor

I have a predictor variable of type factor which contains the date of birth. From your experience (when dealing with logistic regression), what is the best way of treating date of birth (or similar ...
2
votes
1answer
44 views

What factor (trials or blocks) to use in a repeated measures ANOVA

I am conducting a psycholinguistic experiment. Each trial consists of the subject responding to a word by pressing a button.The design of my experiment is as follows: 5 blocks of a 100 trials each ...
0
votes
0answers
32 views

Simplfying summary statistic output stratified by a categorical variable in R [migrated]

Program being used I am using the statistical program R to analyze some data and have what is likely a fairly simple question. Background to the problem I have a variable full of numeric values ...
1
vote
0answers
15 views

Log-linear analysis vs Breslow-day test

I would like to test independence of several categorical variables for a few datasets. I believe Breslow-day is possible for some of the analyses I want to do, and log-linear may be possible for all, ...
0
votes
0answers
22 views

Preparation of categorical data for hierarchical clustering

I would like to use R to perform a hierarchical clustering of data that looks like this: L1 L2 L3 F1 p pr r F2 p NA r which is supposed to ...
0
votes
1answer
52 views

When is it valid to include interaction terms in a regression model? [duplicate]

I am using logistic regression to analyze some categorical data (binary response variable and categorical -- mostly binary -- predictor variables). For my model, I have something like ...
3
votes
1answer
163 views

Interpreting interaction terms in logit regression with categorical variables

I have data from a survey experiment in which respondents were randomly assigned to one of four groups: ...
0
votes
0answers
7 views

How to convert contineous variable to descrete in R? [migrated]

I have a variable which encodes group ID: d <- data.frame(group = c(0,1,0,2,1,3,2,0,1,2), x=c(1.2,2.3,3.2,2.1,1.3,1.5,2.3,0.4,1.3,1.7)) When I try to use it ...
3
votes
2answers
142 views

Getting rid of a huge categorical factor in multiple regression

I have a large regression problem with a lot of cases, but relatively few independent variables. One of them is a categorical factor with thousands of levels. Robust regression runs forever. In some ...
1
vote
1answer
47 views

Dummycoding based on clustering from OM distances

I'm using TraMineR to determine a certain clustering based on Optimal Matching distances: ...
0
votes
0answers
49 views

Variables selection (continuous and classification): how to do in R?

My dataset have both classification (categorical) and continuous variables, ~ 300 variables in all. I'm looking for a way to reduce my attributes to be less than 300 and put them in the decision tree ...
0
votes
0answers
71 views

Analysis to use with categorical response and categorical predictor variables

I have data from a randomized survey experiment in which each respondent was assigned to one of 4 groups, one of which can be considered a "control" or "no treatment" group. The key question asked in ...
3
votes
3answers
272 views

How to do regression with effect coding instead of dummy coding in R?

I am currently working on a regression model where I have only categorical/factor variables as independent variables. My dependent variable is a logit transformed ratio. It is fairly easy just to run ...
2
votes
3answers
136 views

How can I test the same categorical variable across two populations?

I have data that looks a little something like this: ID Status 01 A 02 G 03 E ... ... 100 G You get the idea, I ...
1
vote
1answer
108 views

RandomForest factor with too many levels

I have a model with about 200,000 training observations, where I am regressing, with 4 factors and 2 continuous variables. One of my features has 927 levels, which is causing the R implementation of ...
0
votes
0answers
104 views

Factor Scores of Ordinal Confirmatory Factor Analysis

I calculated a CFA with one latent variable; all four observed variables are ordinal. How can I compute the factor scores? Does anyone know a simple aproach? Some technical background: I'm working ...
2
votes
1answer
180 views

How does anova.lm in R calculates “Sum Sq”?

I'm learning R and trying to understand how lm() handles factor variables & how to make sense of the ANOVA table. I'm fairly new to statistics, so please be ...
2
votes
3answers
377 views

Non-significant intercept in regression with a two level factor in R

I have a linear regression with two explanatory variables. One of them is a two level categorical variable. When I perform the fit, R tells me that the intercept is highly non significant. When I ...
1
vote
1answer
586 views

ANOVA or Regression? 1 Continuous factor & 1 Categorical factor with continuous response variables

I have 1 categorical factor (3 treatments) and 1 continuous factor (weight) and then I have 5 continuous response variables. From what I have read, I should not use a two way ANOVA as one of the ...
0
votes
1answer
164 views

How can I interpret coefficients of categorical predictors in the negative binomial regression model?

I used some categorical variables as predictors to a negative binomial model. The dependent variable is numerical. I used glm.nb in R and the results show relative coefficients of one category ...
1
vote
0answers
23 views

Is there any theory governing factors vs flags

I'm doing some work in R using the gbm package. I'm curious about the repercussions of treating categorical variables as ...
-3
votes
1answer
522 views

How to call glm when response variable is categorical in R?

I have following data stored in a file. I am applying 'glm' in R to find linear regression equation to best predict the 'output'. ...
2
votes
2answers
514 views

Plotting logistic regression interaction (categorical) in R

Hello I have the following logistic model with a categorical variable interaction which I wish to plot in R but I am struggling to find any solutions - ...
0
votes
0answers
172 views

R randomForest for classification error: NA/NaN/Inf in foreign function call (arg 1) [closed]

I am trying to do classification with randomForest, but I am repeatedly getting an error message for which there seems to be no apparent solution (randomForest has worked well for me doing regression ...
1
vote
0answers
258 views

Categorical and dummy variables in multiple factor analysis with FactoMineR

I'm interested in using multiple factor analysis to analyze data collected from ceramic sherds. The data is pretty complicated, containing both continuous variables (vessel rim diameter, vessel wall ...
1
vote
0answers
55 views

Model for multivariate ordered categorical data with a time-varying continuous covariate

I would like to develop a model for multivariate ordered categorical data that also allows inclusion of a time-varying continuous covariate. This is for different types of adverse events, that can ...
1
vote
0answers
57 views

Poisson State Space with AR(1) latent process

I have been trying to use sspir R package to estimate the following Poisson model: $Y_{t}\sim Po(\exp(\lambda_{t}));$ such that $\lambda_{t}=X_{t}\beta +\gamma_{t}$ and ...
4
votes
1answer
145 views

Comparing minitab output to R

I am trying to recreate analysis of diamond data in R and compare it to minitab output cited in http://www.amstat.org/publications/jse/v9n2/datasets.chu.html I'm almost certain its the same data set ...
2
votes
1answer
192 views

Do categorical variables have to be dummy coded in SVM?

I am using R with the packages kernlab / caret and doing some analysis with SVM (ksvm). I am using a Radial Based kernel for classification. I have a few ...
0
votes
1answer
138 views

Flexible discriminant analysis with discrete predictors in R

I am using the mda package and in particular the fda routine to classify in term of gear a set of 20 trips. I preformed a ...
1
vote
0answers
371 views

Test for effects of two categorical variables on a binary response variable?

I am looking for a test similar to a 2-way ANOVA that would work on a binary response variable. My response variable is survival of plant seedlings (alive or dead). My explanatory variables are ...
2
votes
1answer
77 views

Looking for significant variability of categorical data in columns of data frame

I have a data frame with each column contains categorical data: 0,0.5,1,-1 ...
11
votes
2answers
541 views

Alternative to sieve / mosaic plots for contingency tables

I once stumbled across a type of plot for categorical data (i.e., contingency tables) on the internet, which I really liked, but I've never found it again, and I don't even know what it's called. It ...
2
votes
1answer
125 views

Scaling mixed models for PCA using dudi.mix

I am trying to do a kselect model from the adehabitatHS which uses commands from ade4 package. I am trying to determine if I ...
1
vote
0answers
530 views

How do I create a categorical scatterplot in R like boxplots? [closed]

Does anyone know how to create a scatterplot in R to create plots like these in PRISM's graphpad: ...
0
votes
1answer
75 views

Weighted Distributions in Predictive Model

I'm not a statistician but do work with large datasets and have a problem I'd like to use a predictive model for. I have two datasets that I'd like to use together to build predictions. The first ...
3
votes
0answers
284 views

How to interpret p-values for factors

I have fitted a Poisson model to my data in R which includes two factors as independent variables. Each factor has 5 levels. I have used the ...
1
vote
4answers
813 views

What hypothesis test to use for categorical variables? Possibly in R?

Edit: I think this is a better question, Say, I have categorical characteristics such as gender, race. How should I use Fisher's test and chi-square test? I was looking at this: ...
2
votes
1answer
256 views

What is the role of a categorical predictor in polynomial regression?

I understand that there is a function in R called poly() that can generate orthogonal polynomials--useful for applying on input variables before running a ...
2
votes
1answer
306 views

R Formula that only uses a subset of a factor

What is the least painful way to do the following in R? We want to run a model with a formula like this: Model #1: Speed ~ male + female Unfortunately, our data ...

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