# All Questions

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### Can I perform hyperparameter tuning inside K-fold CV?

I am performing lease one subject out cross-validation, using one subject as the independent final test set to get the performance of my model. Can I perform hyperparameter tuning inside each of my K-...
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1 vote
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### How to derive solution to loss function of GLasso for precision matrix

I am trying to find the parameter $\hat\omega = min_{\omega}\Big(-log|\omega| + tr(S\omega) + \sum_{i,j}\lambda|\omega_{ij}|\Big)$ This is to regularize the precision matrix $\omega$ for the GLasso. ...
3 views

### How to cluster binary data using excel or pandas dataframes? [closed]

I have a CSV with 101 rows and 150 columns. I need to find a way to segment/cluster the ID's using the Column values. It can be a machine learning approach or just using Excel techniques. At the end ...
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### Proof of partial correlation formula [closed]

Given two regression: yt = αy+βywt +uy,t xt = αx +βxwt +ux,t Prove that ρx,y|w = cor(x, y)−cor(x,w)cor(y,w)/sqrt((1−cor(x,w)^2)sqrt((1−cor(y,w)^2)
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### How to generate confidence interval for population proportion for a multi class variable

I need to find the appropriate test for the following scenario: I have a population (let's say of an unknown size, for now) which I sampled from it and found the following distribution for some ...
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### can i compute an interaction variable by multiplying a standardized variable and a mean centered variable?

I need to do a multiple hierarchical regression analysis for my master thesis. my continues independent variable is: online exposure to cannabis use. I used five items/questions/variables to compute a ...
11 views

### Interpreting error bars when conducting a one-sided test

I have learned that when interpreting error bars on a bar chart, given that the sample sizes are equal (or nearly equal), that we can trust the error bars if they overlap (or not) in terms of ...
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### What is the uncertainty of Leave-one-out-cross-validation method?

I have used the LOOCV to validate my model. As we know, the LOOCV method is a special case of cross-validation where the number of folds equals the number of instances in the data set. Thus, the ...
1 vote
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### How to simulate events in certain time?

I am trying to make simulation, and I have some events that happened durring a day. Some times it s for example few events durring half hour for one day, and sometimes we have event, and then few ...
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### Statistical comparison of hierarchical data with pair-wise comparison

I am a bit confused how to use hypothesis testing here and please let me know if this question was already asked. Imagine the following hierarchical setup: There are 8 schools in a city. Within each ...
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### ANCOVA - Follow up tests

Which follow up tests should be used with an ANCOVA to make sure the covariate is included in the assessment ? I’m struggling to find an appropriate test for this.
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### Is there a mathematical way to show why exactly adjustment for baseline helps in longitudinal randomized studies and NOT in non-RCTs?

How exactly adjustment for baseline helps to minimize the bias and increase effectiveness in randomized trials? I heard about: it minimizes the unexplained variance - but how? it minimizes the ...
1 vote
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### Under what circumstances is a m-class classification Neural Network equal to a base category logit model for nominal responses

Here is the setup for an m-class classification neural network. $$z_j=\sigma(\alpha_0j+\alpha_j^T x), (j=1,...,k)$$ $$t=\beta_0+\Sigma^k_{j=1}\beta_j z_j)=\beta_0+\beta^Tx, (l=1,...,m)$$  y=f(x)=g(t)...
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### Help with performing a time series analysis for Master Thesis (with R) [closed]

I was wondering if you guys had any advice on how to perform a time series analysis? For the context, I would like to analyze the link between projects related to video games on Kickstarter and the ...
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### Euclidean distance between points in PCA space along different principal component dimensions

I've picked up this project half way through, and I'm working through the last guy's code, so please bear with me. So the original data consists of 500+ points in 150 dimensions, and I want to ...
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