# Tagged Questions

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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### Duncan’s statistical test for blocks designed experiment with full factorial scheme

EDIT: Already got an answer to question 4 (programming). Question will remain on theoretical issues about factorial experiment designed in blocks and Duncan's test. Given one experiment designed in ...
436 views

### R p-value half to SPSS rANOVA

I have done rANOVA in SPSS and then in R and got two different p-values from the same model. While SPSS gives 0.032, R gives 0.0162, which when rounded is a half. Other data are exactly the same. 1. ...
436 views

### Bounded response variable [-1;1] - Should I transform it?

I am planning to use two response variables. One is bounded between 0 and 1, and I guess I can use a binomial (or related) error structure. The second variable is bounded between -1 and 1. I am not ...
14k views

### How to reconstruct original data using a small number of principal components?

I have a big dataset of $\pm 40000$ observations, each containing $784$ variables. Because this dataset is extremely large I want to perform a dimensionality reduction. Now everywhere I read that I ...
154 views

### Methods For Estimating Trend in R [closed]

Do you know how i can get a code for estimating trend by Mitcherlich and logistic method in R?
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### Measure the relation/association between the outcome and the independent variables

I am running a model (logistic regression) with 20 independent variables in R. Before running the model I calculated the correlation between all the variables and finally selected my variables by ...
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### Performance indicator for imputation method using R

I have a 10 imputed air quality data using 7 different method of single imputation. can someone show how to compute MSE,RMSE,PA and MAE for my data, without manually type the equation in r. ...
317 views

### Correct formula for standardized Student's t-distribution

I am wondering about the correct formula of the standardized Student's t distribution. In the rugarch package on page 15 it is given as: Substituting $\frac{(\nu-2)}{\nu}$ into 49 we obtain the ...
183 views

### The coefficient of one variable in Cox regression becames negative when doing multiple variable regression

I am doing Cox proportional regression. I first did Cox regression with only one variable var; its coefficient 0.8752721 was about what I expected and is easy to ...
10k views

### How to test for overdispersion in Poisson GLMM with lmer() in R?

I have the following model: > model1<-lmer(aph.remain~sMFS1+sAG1+sSHDI1+sbare+season+crop +(1|landscape),family=poisson) ...and this is the summary ...
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### What does it imply when an estimate is not inside its 95% confidence interval? [closed]

What does it actually imply when a 95% CI does not contain an estimate (coefficient or parameter). Is there some model assumption that has not been satisfied? Or it means something else? I know when ...
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### Mixed-effect modeling with paired observations & bounded response variables

I am quite new in the field of mixed-effect modeling. For a beginner like me, I guess I combine several levels of complication in my analysis: paired observations & bounded response variables. I ...
540 views

### Converting ARMA models to infinite AR process in R

I'm trying to recreate some test statistics that use the infinite AR representation of normal ARMA models. I found out about the function ARMAtoMA but have not been able to find the same functionality ...
786 views

### How to rank predictor variables in logistic regression in R [closed]

I have created a logistic regression model in R. The dependent variable is binary whether or not a landscape transitioned to another cover class denoted by 1s and 0s, and the independent or predictor ...
410 views

### Is it correct to say the “smooth curve fitted by LOESS”?

I use the package scatter.smooth in R, and I want to have a figure text describing the line in the scatterplot for my report. Is is okay to say "the line is a ...
639 views

### Restricting model parameters in logistic models in R

Is there any function in R that can solve the problem like this example from the SAS website: Beginning in SAS 9.3, PROC FMM can be used as an alternative to ...
880 views

### Blocked repeated measures ANOVA in R

I am trying to test if richness varies by treatment (Severity) over time (Block) using a repeated measures ANOVA in R. Any suggestions on how to do this correctly? I have tried, but get an error ...
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### Implementation of Dirichlet cdf?

I need to compute the Dirichlet CDF, but I can only find implementations of the PDF. Do you guys know of any library (preferably in R) implementing it?
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### How is the Df computed in a mixed model?

The following is the output for a mixed model example. The only difference between fm1 and fm2 is the random factor "URBAN", why the df for fm2 is 5 but not 4? Any help would be great. ...
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### Pretest-posttest plus control design

I am evaluating the effect of an intervention (treatment: a lecture) on the ability to spot behavioral clues of emotions using visual stimuli using pretest-posttest plus control group experimental ...
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### Confidence Bands in non linear mixed effects models

Is there a way to get confidence bands around the fitted population fixed effects curve for non linear mixed effects models fitted in R function ...
494 views

### Compute cdf and quantile of a specific distribution

I want to calculate a quantile of a specific distribution. Therefore I need the cdf. My distribution is a standardized Student's-t distribution, this can be written as \begin{align*} f(l|\nu) =(\pi (\...
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### How to calculate 95% CI for a random effect?

The R code "intervals()" gives confidence intervals for fixed effects only in a mixed model. *Is there a reason why only fixed effects' confidence intervals are provided? *Is there any way to get ...
449 views

### How to interpret the frailty terms in a coxph.penal model?

I have the following coxph model: Surv(Y) ~ genotype + treatment + age + frailty(batch) + genotype:frailty(batch) ...
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### Energy estimation through machine learning

Greedings to everybody. I have the dataset which you can find here, containing many different characteristics of different houses, including their types of heating, or the number of adults and ...
158 views

### A distribution similar to the Poisson one?

I have a set of data which in my opinion can be treated as coming from a Poisson distribution (they are all positive and represent days). I need to perform several regressions, with R, using these ...
2k views

### spatial autocorrelation for time series data

I have a 20-yr dataset of an annual count of species abundance for a set of polygons (~200 irregularly shaped, continuous polygons). I have been using regression analysis to infer trends (change in ...
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### Do the predictions of a Random Forest model have a prediction interval?

If I run a randomForest model, I can then make predictions based on the model. Is there a way to get a prediction interval of each of the predictions such that I ...