All Questions

0
votes
0answers
4 views

What are the two main parameters in K-Means? [on hold]

What are the main parameters in K-Means and What is the main problem of K-Means clustering algorithm
0
votes
0answers
3 views

How do I prepare my data for sequence analysis in STATA? [on hold]

This is my first time performing sequence analysis, I want to come up with precarious employment trajectories, so I have already some variables prepared that measure in months when was a specific ...
0
votes
0answers
2 views

How to calculate contribution, ROI, and mROI from marketing mix model?

I've begun to read the books MARKET-SHARE ANALYSIS and Market Response Models on how to estimate marketing mix models, but, while they thoroughly detail how to model the response to promotional ...
0
votes
0answers
3 views

How to correlate values in the same column by group using groups in another column

I have a dataset that looks like this in R: ...
0
votes
0answers
2 views

IOU vs ROBIN metrics

Came across this paper on ROBIN evaluation metrics. The metrics seem to be more informative than just IOU, so is there a reason why IOU is the preferred metric in most cases for object detection. ...
0
votes
0answers
4 views

How does one compare two nested quasibinomial GLMs?

Lets say I have two models: Model 1 and Model 2, both of which are used to fit a quasibinomial GLM on some 0/1 response data (that I believe has overdispersion, hence quasibinomial GLM instead of ...
0
votes
0answers
8 views

Adapting Cox Regression to Time dependent continuous variables

I am interested in using cox survival regression model when the covariates are not expected to be constant over time and also continuous. I did check a few books and the time dependent Cox Regression ...
0
votes
0answers
10 views

Calculating the posterior distribution of linear predictor

I am currently fitting a linear regression model in a bayesian framework in R with the package ngspatial. To investigate the quality of fit, I would like to calculate the bayes R2, as suggested here ...
0
votes
0answers
10 views

How to check if i have strong linear relationship between dependent variable and independent variables in ols?

I want compare the out of sample prediction from an ols model and a regression tree. I read that ols outperforms regression tree if the relationship between the dependent variable and independent ...
0
votes
0answers
9 views

Is Oversampling beneficial in semi-supervised learning?

I have suggested a semi-supervised approach for the hierarchical multi-label classification task. I have included the MLSMOTE oversampling technique as a pre-processing step, and then evaluate the ...
0
votes
0answers
9 views

Linear Programming/optimisation with R? [on hold]

I hope this isn't a repeated question, but: does anybody have a firm idea of how much data can be handled by R when doing a linear optimisation model? For example, will R be able to handle ...
1
vote
0answers
10 views

Understanding PCA from a linear transformation perspective

I've came across several great questions and answers here regarding PCA, but I would like to have a look at it from a linear transformation perspective. Let's say I have a (demeaned) data matrix $X$ ...
1
vote
1answer
6 views

Should subscales be analyzed separately under the IRT Graded Response model?

Suppose I have a Likert scale type questionnaire that assesses the amount of social support a patient receives. The questionnaire is divided into four subscales that measure: Emotional support ...
0
votes
0answers
16 views

Parametrs of the Uniform Likelihood

Consider linear scalar model $y_k = x_k + w_k$ where $w_k \sim U(a,b)$. What we can say about the probability distribution $p(y_k|x_k)$? We can show that $p(y_k|x_k)$ have uniform density, but I ...
0
votes
0answers
13 views

Error in R Random Forest package [on hold]

This is my train_set: I'm trying to predict monetary using RandomForest package with: <...
0
votes
0answers
12 views

Can I work around a small number of samples in a logistic regression? [duplicate]

I am deeply frustrated, I have a dataframe with a small number of samples (N=13) and am trying to do a logistic regression with binomial variables. I know, that especially given that there is an even ...
0
votes
0answers
5 views

K-Fold Cross Validation: Bias in cross-validated effect size measures?

As pointed out by various authors (e.g., Hattie, 2011), K-fold cross-validation has an upward bias of prediction error. I wonder whether the same holds for cross-validated effect size measures such as ...
0
votes
0answers
9 views
0
votes
0answers
7 views

Predict Taking a Loan

I want to build a Logistic Regression model to help me predict taking a loan by a customer base on several variables. I started building a data set for the customers who already took loans and some ...
0
votes
0answers
4 views

how svm from e1071 works with k>2

I'm pretty new to R and machine learning and I'm doing an analysis on a dataset. I'm tryng to use the svm function from the e1071 library but I'm wondering if it takes care of number of classes. I ...
0
votes
0answers
9 views

Minimax equivalence of Matrix Norm

In a proof of random matrix theory, the author makes use of the following equivalence: \begin{equation} \inf_{v\in V(r)}\lVert Xv \rVert_2 = \inf_{v\in V(r)} \sup_{u \in S^{n-1}}u^TXv \end{equation} ...
0
votes
0answers
21 views

Interaction significant, simple effects not

I'm running a regression which showed a significant interaction effect between my variable design (0,1) and device (0,1) on view time. However, i did not found a main effect of design on view time. ...
0
votes
0answers
10 views

Multiple non-linear regression with weak correlation [on hold]

a question about multiple non-linear regression. What I did - using GAM family = Poisson regression, my goal is to estimate the relationships among variables. ...
0
votes
0answers
10 views

Glmnet default values [on hold]

I am using the glmnet package to find biomarkers from a dataset. I only tell the function my x and y vectors and my alpha but no family (such as binomial, gaussian etc.). What would be the default ...
0
votes
0answers
20 views

Doubt in Monte Carlo sampling [on hold]

I came across this in page 491 of the book "Deep Learning" by Goodfellow: I wanted to know what exactly are they doing here? I could not understand the statements being made to justify the sampling ...
1
vote
2answers
15 views

How to analyze correlation of multivariate time series

I have a multivariate time series with variables A, B and C. ...
0
votes
0answers
7 views

Consistent estimation and valid inference when performing regressions on data with differing levels of granularity

Imagine that a dataset has a combination of variables of differing levels of granularity (e.g. an international sample of firms containing both firm-level and country level information). There are $K$ ...
0
votes
0answers
34 views

Sum of two dependent normal random variables is not necessarily a normal

Let $X\sim \mathcal {N}(0,1)$ and $W\sim \mathrm{Bernoulli}(\frac12)$ be an independent random variables.Define the random variable $Y$ as a function of $X$ and $W$ $$ Y= h(X,W)=\left\{ {\text{X, if ...
1
vote
0answers
10 views

Training Neural Network with Simulated Annealing

I am trying to train a simple neural network with simulated annealing. I have programmed a neural network with an input layer of 784 input nodes (28 x 28 pixels, I am using the MNIST database to train)...
0
votes
2answers
27 views

Show statistical significance (or not) between means

Suppose I have two experiments A and B. Each experiment is composed of N elements that are clearly separated into two groups. In experiment B one of the groups has a higher mean than the same group in ...
0
votes
2answers
24 views

Appropriate model choice for analyzing a cluster based longitudinal randomized controlled trial

I am performing a randomized controlled trial (RCT) of an educational intervention to improve knowledge, belief and practice among healthcare workers in hospitals. One hospital is assigned to the ...
1
vote
0answers
9 views

sample size to detect variability in a sample

I have a sample of continuous data which I use to build a random forest model. Now I want to determine, how many additional samples I would need to improve the prediction (reduce the RMSE by a certain ...
1
vote
1answer
20 views

Unusual Markov inequality for normal distribution

I'm trying to answer the following question from Larry Wassermans book on statistical inference. My question is how did they arrive at the Markov bound, it does not seem like the normal form of the ...
0
votes
0answers
7 views

On an alternative filter for a particular class of state space models

Let $ \{ X_t \}_{t \in \mathbb{Z} }$ be a real valued time series that can be represented in a state space form, in particular assume that the sequence $ \{ X_t \}_{t \in \mathbb{Z} }$ satisfies an ...
1
vote
1answer
11 views

Enforcing Dirac delta-like Activations on a Neural Network

I am working on a custom neural network model including convolutional and dense layers. I intend to enforce outputs a certain dense layer to approximate a Dirac delta function (or any localized pulse)....
0
votes
1answer
16 views

A Strict Sense Stationary (SSS) process implies it is a Wide Sense Stationary (WSS) process - proof

Looking for a mathematical proof which shows that a Strict Sense Stationary (SSS) process is necessarily a Wide Sense Stationary (WSS) process.
0
votes
0answers
7 views

Data Analysis using SPSS in Chi-Square Test [on hold]

I want to analysis newspaper contents using the Semetko and Valkenburg (2000) five news frames. Please which is the best statistical analysis to use in conjunction with the chi-square test. can ...
0
votes
0answers
6 views

Binary text classification with a variable amount of documents per labeled datapoint

I have a dataset with a label TRUE or FALSE for each person, but each person has multiple documents associated with them (emails ...
1
vote
0answers
6 views

Recognizing whether a written and spoken number is the same

For our ML assignment we have three datasets. The challenge is about checking whether a written and spoken number refer to the same number. We're using the MNIST dataset with handwritten numbers, and ...
0
votes
0answers
5 views

gogarch package

I have read the description to gogarch package, but i don't understand the function of external.regression option in that package.. How it is working ? could you give an example? ...
0
votes
0answers
14 views

Lasso, ridge and elastic net regression using package h2o [on hold]

So basically when fitting a lasso estimator and ridge regression, all variables are kept in the model(none of them are shrunk exactly to zero). Now for ridge this is normal, but for lasso some of them ...
0
votes
0answers
10 views

why is VAE reconstruction loss equal to MSE loss

At which situations does reconstruction loss of VAE equals MSE loss between input and reconstructed output? Other answers where not complete!
1
vote
0answers
9 views

How to calculate a permutation confidence interval?

Mara Tableman, Minh Nguyen, and Michael D. Ernst note The idea behind a permutation confidence interval is well known and fairly straightforward (Ernst 2004). The confidence interval is simply the ...
1
vote
0answers
22 views

Is it possible to get too small McFadden R^2 while at least one variable is significant?

I am quite new in logistic regression. I tried to apply a logistic regression on a dataset with 3 independent variables: Gender (Categorical- either male or female), Freq_A and Freq_B (continious ...
1
vote
0answers
9 views

OLS - Predeterminedness and moment condition

I'm having trouble validating if following procedure to test for predeterminedness is plausible. Given the linear model: $y_t=\beta_1+\beta_2x_{1t}+\beta_3x_{2t}+\epsilon_t$ Having $x_{2t} = y_{t+1|...
0
votes
1answer
9 views

Multi-task learning: weight selection for combining loss functions

I am training a system that combines two sub-systems: one for classification and another for reconstruction. Can anyone suggestion what are the common practice for weight selection for combining two ...
1
vote
1answer
6 views

How to apply INAR model to a simple time series model in Python

As a course project for Time Series Analysis, I used ARIMA for a very simple model - (Analyzing number of deaths in each episode of game of thrones and forecasting the number of deaths in the final ...
0
votes
0answers
10 views

Known Correlation between predictors

I have two predictors and an outcome, let's call them x, y and z. I know that x and y are correlated with correlation r. I am trying to construct a linear model: z = ax + by + c I have an ...
0
votes
0answers
9 views

What are other nonlinear transformation methods except Sigmoid, ReLU, Tanh etc?

One advantage of the MLP neural networks is the nonlinear transformation used on raw features. The popular ones used are the activation functions like Sigmoid, Tanh, ReLU, Leaky ReLU, etc. They are of ...
1
vote
0answers
10 views

How to calculate Bhattacharya distance for multivariate normal distributions if determinant of covariance matrix is approximated to zero

I am applying Bhattacharya distance for multivariate normal distributions $D_{B}={1 \over 8}({\boldsymbol \mu }_{1}-{\boldsymbol \mu }_{2})^{T}{\boldsymbol \Sigma }^{{-1}}({\boldsymbol \mu }_{1}-{...

15 30 50 per page