# All Questions

140,566 questions
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### Modeling repeated measure effect with linear mixed effect models (lmer) in R

this is the first time I'm posting a question here, I hope someone will read it soon :) I have the following problem: I have three groups of people (ADHD patients, ADHD patients under medication, ...
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### Proof of (weak) consistency for an unbiased estimator

I want to prove a theorem stating: An unbiased estimator $\hat{\theta}$ of the unknown parameter $\theta$ is consistent if $V(\hat{\theta}_n$) $\to0$ for ${n\to\infty}$. I've tried using the ...
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### When to use the full and the conditional likelihood

In the context of estimating parameters of a time series model, we may consider either the full likelihood or the conditional likelihood. I was wondering 1) when does one use the full ...
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### How to test nomological validity with lavaan?

in my understanding, I need to test nomological validity with SEM. But what exactly should I look at in e.g. summary(fit1, standardized=TRUE, fit.measures=TRUE)? Code for reference: ...
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### Understanding concepts of regularization

I am trying to understand regularization in machine learning. But, I do not understand some fundamental concepts in this topic, could you please explain? A model that has high variance, captures ...
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### How to forecast the future values ( test data) by making use of the fitted ARIMA model [duplicate]

I am tried as follows But problem is all the fitted values are 39 Data : Test and Train data
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### How can I obtain the cross loadings with lavaan? [on hold]

In my understanding, cross loadings can only be obtained from Structural Equation modeling (i.e. not from CFA) in lavaan. Am I correct? How should I obtain the cross loadings with lavaan? Code for ...
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### Normalization strategies with repeated samples

could anyone direct me to methodologies to perform the following: We measured proteomic profiles of a set of samples at one point, and after looking at the results, we decided to run more samples on ...
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### Electronic equipment failure prediction/abnormal behavior detection model

I have a data set of alarm logs and event logs of network equipment with timestamps and I'm looking to build a machine learning failure prediction/ abnormal behavior detection model using python. ...
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### How do i Remove Differencing applied to a time Series, ARIMA model?

Am trying to forecast using time series method called ARIMA. I have followed steps to build a time series model displayed in the code below. My challenge is on (Merging Actual and Forecast in One ...
24 views

### Random Forest in R. Dataset not symmetrical [on hold]

I did a couple of training with RandomForest in R for a class problem (event must be 1 or 0). Dataset consists of 10.000 rows and 10 variables (more or less) and each variable is built like ...
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### Calculating confidence intervals from 2-level samples

Let's say we have a 2-level sampling process that generates N groups of M values: x[i][j] is the jth value from the ith group. For each group, there is a value g[i] that we can't observe directly. ...
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### What is the simple explanation for the fact that L1 norm gets increased faster around the origin than L2?'

L1 norm gets linearly increased around the origin while L2 norm doesn't( it does but at a slower rate)? Can anybody provide a simple explanation for this? L2 norm is given by the square root of (x1^2+...
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### Interpreting results of Fuzzy C Means Clusters

I currently have the Fuzzy C Means clustering algorithm implemented in python and it works quite well. What can be said about the number of observations within each cluster? If each observation ...
12 views

### Comparing survival times in overlapping groups

I have a following statistical setup I don't know how to attack: I have two therapies: say A and B. For some patients A works better, for other B works better. I want to direct patients to their ...
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### Nataf's or Rosenblatt's Transformation for Discrete Random Variables

I have discrete random variables (with Binomial distributions). I would like to transform them to the standard normal space. Nataf's and Rosenblatt's transformation are suitable for continuous ...
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### Understanding variance stabilization and its uses

I recently came across the variance stabilization method that tries to remove the dependency of variance from the mean(for example consider poisson distribution). ...
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### Modelling geographic data as supply - alternative to KDE [on hold]

I'm trying to model supply vs demand for geographic data. Originally I was using KDE to "smooth" this data out over a certain radius / bandwidth. This makes sense for some types of supply like lets ...
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### How create a heteroskedastik robust probit model in R?

I would like to replicate the function in Stata "dprobit (function, r)" with R - Studio. I've tried "glm(..., family = binomial (link = "probit"), data =...) in R. But it leads to different results, ...
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### Questions on variables regarding multiple linear regression. Percentages and ratios + standardisation [on hold]

I am new to statistics and regression analysis. For our R class, we are required to perform linear regression. Dependent variable: P/E ratios of firms Independent variables: revenue growth (in %), ...
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### Comparing means, having a large variance

Currently I am working on a project in which i do have two different sample-sets with a limited size and a large variance. Furthermore, I do have a bigger data-set that gives information about the ...

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