Use this tag for any *on-topic* question that (a) involves `R` either as a critical part of the question or expected answer (b) is not *just* about how to use `R`.

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1answer
3 views

Random Coefficient Negative Binomial Model

I have a crash count data and i want to build a random coefficient negative binomial model in R. The dependent variable will be the crash counts and covariates will be Lane width, AADT, shoulder width ...
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0answers
2 views

Jackknife estimator for coefficient of variation

I have one of the estimator of coefficient of variation and i am using jackknife method to reduce bias. I am running R code to do the simulation for this study. The result i am getting is not what i ...
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0answers
10 views

Getting the Estimate of ref Level in Multiple Regression with Dummy Variable in R

I have this regression model in R using dummy variables ...
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0answers
5 views

Can I use deviance to compare the fit of a model to different datasets?

I'm using R's nls to fit different datasets to the same model. I've read that using R-squared is usually not correct for ...
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0answers
9 views

Forecasting daily visits using arima and external regressors

I have daily visitors data for last 10 years, i want to do some basic tests like which is the busiest day , which is the busiest month, busiest week etc.i used auto.arima and xreg function to find out ...
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0answers
9 views

How does the “summary” function that is run on a principal fitted components function work?

I'm playing around with the ldr package in R, which comes with Big Mac data. If I run this code (which is similar to one of the examples): ...
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0answers
18 views

Fitting an envelope to x-y data in R

I have some data that I'd like to create an envelope for it. As in the picture, the data is always positive and I'm looking for something that will capture my crudely hand drawn red line. It should ...
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0answers
10 views

Different variance estimator for multilevel ordinal logistic regression in Stata and R

I estimate a multilevel ordinal logistic regression models in Stata and R, and receive different estimators for the variance and the covariance of the latent variable of the higher level. Among other ...
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0answers
9 views

R and fisher test in each row in a data frame [on hold]

![enter image description here][1] I basically have this dataframe and I would like to do a fisher test on it to see which of thoses elements are present more ...
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0answers
9 views

skip -9999 and perform multiple regression [on hold]

I want to do the multiple regression where SMDI is my dependent variable and other are my independent variable. I have following dataset to do the multiple regression: SMDI ET PRCP ET_Ch ...
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0answers
6 views

generating a sequence of indicators based on variable boundaries in JAGS

Suppose I have a vector of indices 1:N, and data y[1], ..., y[N]. I have three variable center points in ...
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0answers
20 views

Poisson Distribution - rpois - NAs produced [on hold]

I am new to R (a student) and running a Poisson distribution on football scores. head(results0910) works perfectly, showing me that my teams and scores are read in ...
0
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1answer
21 views

Measuring impact of advertising on retail sales

I have a dataset of retail products which contains weekly sales for 12 different items in a single category. For each item, I have three dummy variables representing different types of advertising ...
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0answers
34 views

Difficulty plotting regression in R

I am trying to plot a regression using plot() and keep getting the error message "Error in xy.coords(x, y, xlabel, ylabel, log) : 'x' and 'y' lengths differ". ...
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2answers
13 views

Prediction of features given predictor

I am working on a problem where my objective is to predict y given some features x1,x2,x3,...x8,x9 I solved this problem using some statistical and machine learning techniques like regression, trees, ...
0
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0answers
16 views

Two-Way Repeated-Measure design with lme4

I would like to model a treatment effect in two different groups, controlled for some co-variates (like age and education), and I assume that a two-way repeated-measure Anova would be the right ...
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0answers
20 views

Assessing the need for random effects terms

During the model selection phase for mixed models, there are typically several possibilities to choose from; in fact, the number of possibilities is increasing in the number of covariates used. How ...
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1answer
14 views

Do the values in the second factor from a principal component analysis have to have different signs?

I am computing the principle component matrix of a financial database and to obtain the second factor I extrapolate the second vector. So far, it's easy, but I wonder, do the signs of the second ...
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0answers
6 views

Calculating Diversity using normalized species counts

I am trying to calculate the change in diversity of species encountered throughout time. My dataset is comprised to detections of tagged fish for 48 consecutive weeks. My thought was to bin the ...
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0answers
9 views

which package in R perform k-prototype algorithm? [on hold]

I have mixture of nominal and discrete numerical data.I want to cluster the data and as i know some clustering algorithms such as k-means are not appropriate for clustering mixed data.So i want to ...
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0answers
17 views

Stat test to use with nominal variables

I have a research question looking at whether one level of a nominal variable is more likely to elicit an action than another. We are using a control and experimental group so our IV is either ...
1
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1answer
21 views

Sampling intercept and slope pairs from lm in R

Let's say I have a model Y~X+trt, and by running lm and summary functions in R I get these results: ...
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0answers
25 views

Correlation with categorical variables - Interpretation of aov()

I want to know if one (or more) out of three categorical variables (season of measurement, geology, grazing) influence the numerical variable (spread of a plant). Sure, I read the answers here ...
0
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0answers
15 views

Copula Quantiles in R? [migrated]

I have the following bivariate Copula models: Archimedean copula family:- Gumbel-Hougaard Copula ( Model-1) Frank Copula ( Model- 2) Elliptical copulas family Normal Copula(Gaussian Copula) ( ...
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0answers
6 views

Aggregating Equity Intraday Ticks

I am currently working with intraday equity data. The ticks are sourced from Bloomberg API. Bloomberg only timestamps down to the second (not millisecond) and data is not in order. In many instances ...
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0answers
10 views

Find significantly different element

I have following data and want to know is there really significant difference between those five objects: I have 5 objects and 3 different tests and their results like this. So this is very few rows ...
2
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1answer
33 views

Implementing Gibbs sampler in R from posterior distribution

I am referencing a follow-up idea from something I posted earlier (Zero-inflated Poisson and Gibbs sampling, proofs and sampling). I want to implement the Gibbs sampler, by generating a large ...
1
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0answers
33 views

Removing additive effect in Multiple Regression in R

I have this data set that I will used for my model ...
2
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2answers
49 views

kappa coefficient doesn't make sense

I am calculating Cohen's Kappa to assess agreement. Here is my contingency table: 0 1 0 23 17 1 59 457 So the observed probability of agreement is high ...
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0answers
19 views

Is there any argument in GAM function (R software) to tell the model which variables are categorical or continuous? [on hold]

I want to fit a species distribution model for some bat species using a generalized additive model (GAM). I have 124 presence points and I generated 10000 random absence points. I also have 18 ...
3
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1answer
31 views

Discrepancy between metafor and weighted lm() standard errors

My friend and I are trying to understand why a weighted lm() v. a fixed-effect rma model from the ...
3
votes
1answer
26 views

Zero-inflated Poisson and Gibbs sampling, proofs and sampling

I am trying to figure out zip-inflated Poisson (ZIP) model. In this model, random data $X_1, .., X_n$ are of the form $X_i=R_iY_i$, where the $Y_i$'s have Poisson distribution ($\lambda$) and the ...
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0answers
21 views

Stata vs. R survival differences; weibull scale is different, problems predicting manually

I am trying to do some survival analysis in R and as a starting point, I want to make sure I can replicate a previous analysis. I notice differences and I will demonstrate them here. I feel like there ...
0
votes
1answer
14 views

State space models in dlm package - how to add a non time-varying constant?

I am trying to compare the following two models: \begin{align} y_t &= \beta_{0,t} + \beta_{1,t} x_{t} + \epsilon_t\\ \beta_{1, t+1} &= \beta_{1,t} + \eta_t\\ \beta_{0, t+1} &= ...
0
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0answers
7 views

Can I customize preprocesses in R caret's package? [migrated]

I am using the caret package for training regressions. Since I came across of it, I knew I was gonna need it. I have looked at the section for preprocessing the ...
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0answers
7 views

Moment Conditions for Stochastic Discount Factor (SDF)

Following extract has been taken from Computing Generalized Method of Moments and Generalized Empirical Likelihood with R, the Vignette of gmm R package. In some ...
1
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1answer
41 views

Problems with time series prediction

I got a question about modeling time series in R. my data consist of the following matrix: ...
2
votes
1answer
28 views

When is mu_a used in this STAN example?

I'm looking at an example of a random effects model with 2 random effects fit by Peter Li demonstrating how get models fit in lmer into STAN. The code for this and the accompanying data are stored ...
2
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1answer
85 views

R Time Series Forecasting: Questions regarding my output

I'm working on a forecast for the following data: ...
2
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1answer
81 views

Generate data with skewed distribution and known percentiles, mean and median

I'm trying this one again as my imprecise use of language unfortunately confused my last attempt at this question... I am trying to recreate some data from a publication. The study was on levels of ...
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0answers
5 views

R lda() graphing with two groups - histogram or scatterplot?

I am using a discriminant function analysis to see which environmental variables best discriminate my study wetlands into those occupied by a species and those not occupied. I have 23 wetlands and ...
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0answers
3 views

using hclustvar in R, it clusters the column headings but I want it to cluster my row headings

I have a data matrix with quantitative and qualitative variables as columns and species as rows. I would like to cluster the species in terms of the variables, but it keeps clustering the variables. ...
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0answers
8 views

Standardized Regression Coefficients for categorical interactions: lm.beta() vs. regressing standardized variables

I am working with a regression model from which I would like to compute standardized regression coefficients. I am writing primarily regarding an observed discrepancy between coefficients obtained by ...
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0answers
13 views

Maximum number of alternatives in a discrete choice model

We are modeling a discrete choice scenario, with alternative-specific coefficients. We also break the assumption of independence of irrelevant alternatives. To model this, we are using an ...
0
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1answer
14 views

perfect variable separation, determine cutoff via ROCR package in R

I am developing a logistic regression model where perfect variable separation occurs. I want to calculate a cutoff from this data. Interestingly, the length of the slot ...
1
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0answers
16 views

How to merge different predictive models training with different data sets?

Is there any good method to merge/consolidation different predictive models which were trained on different features but outputs the same goal. Example: Model 1 with features a + b + c (trained on ...
0
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0answers
29 views

How to account for repeated measurements and unequal sample sizes in RDA

I have a question going in the same direction as this one: Restricted Permutations However, I have a dataset of multiple Locations from which I have samples of sometimes 5 sometimes only 3 years. Not ...
0
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1answer
30 views

Buiding Ensemble model

I'm new to ensemble model. Suppose I've KNN models like this - (in R) library(class) ...
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0answers
17 views

prediction of class label from training dataset

I have generated class association rules using a training data set. The task is to predict the class label for a new data set without given class labels and verify that the previously rules suit the ...
0
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0answers
20 views

Getting the probability density kernel estimator with R

I am working on a density estimation project and I need to get an estimation of the density as well as an equation for the density estimator (and not the estimate). I am working with kernel ...