# All Questions

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### In a random forest algorithm, how can one intrepret the importance of each feature?

I am in the process of building a Random Forest algorithm in MATLAB using the TreeBagger function. In the documentation, it returns 3 parameters about the importance of the input features. My ...
11 views

### Set all values of a column to zero conditionally by factor level [on hold]

I am trying this in R I have the following variables in a data frame: X1 (numeric) X2 (numeric) ... X100 (numeric) X101 (factor with 5 levels) X1 to X100 are numeric I want to do the following: For ...
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### Model for count data with different exposure time (some times are terminated by death)

I am looking for most suitable model for count data in the following case: we collect number of patient's visits in a hospital for $t_i$ days ($t_i$ varies across subjects) some patients died ...
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### Can I Use DFT To Find The Most Common Frequency?

I have a collection of data which measures the change in state of a device which records information. I basically record the time a new observation is made on the device. I want to collect the data ...
4 views

### Testing Proportional Odds Assumptions

I am working in R with a response variable that is the letter grade the student received in a specific course. The response is ordinal, and, in my opinion, seems logically proportional. My ...
27 views

### how does the beta function make the total probability of Dirichlet distribution integrate to 1? [duplicate]

the Dirichlet distribution $$Dir(\boldsymbol\mu|\boldsymbol\alpha)=\frac{1}{B(\boldsymbol\alpha)}\prod_K\mu_k^{\alpha_k-1}$$ How is the normalization term $B(\boldsymbol\alpha)$ calculated? or in ...
5 views

### clustering segmentation

I am trying to create customer segment using set of customer features. I have dependant variable like revenue of a customer by different product categories. I am trying to create segment that are ...
11 views

### Question about the Probability of Error for Joint-Typicality Tests

Given a set of codewords $\boldsymbol{x}_i$ with $i=1,\cdots,2^{nR}$ where $R$ is the rate of the code. The codewords are transmitted over a Gaussian channel $Y = X + W$ with $X\sim\mathcal{N}(0,A^2)$ ...
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### How to combine a set of features and report their effectiveness with only one number?

I have a binary classification problem. My data set has 100 features with 10 different categories (10 features per category). I want to report the effectiveness (in terms of classification) with a ...
24 views

### Data structure for rare event predictions in temporal domains

I am a beginner in rare event modeling. I am working on predicting modem failures within a network where failures occur approximately 3% of the time. Currently my data is structured as follows: ...
5 views

### invoke pipeline functions in sklearn [on hold]

i want to invoke sklearn pipeline with a function to transform the sparse matrix output from feature extraction process to the guassianNB() classifier ...
11 views

### ML and Flow Maximization

I've been wondering if you guys ever saw ML being used to assist a Max Flow algorithm? I have a very large directed graph that has some fractal characteristics, meaning that this large graph can be ...
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I am working on an ADALINE algorithm in python, and I am printing the graphs in the code, but when I run the program the graphs do not print. Any help with that or suggestions to improve the algorithm ...
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### Poisson regression? [on hold]

If we have a $y_i$ random sample with a $Poisson(\lambda_i)$, $i=1,2,...,n$. Also $\log(\lambda_i)=(X\beta)_i$ where $X$ a known $n \times p$ matrix and $\beta\in\mathbb{R}^p$ is not known. Assuming ...
13 views

### What are scientific questions one may ask regarding a univariate time series?

What are scientific questions that one may ask regarding a univariate time series besides forecasting/prediction?
12 views

### Poisson regression residual analysis

In a three factor poisson (log-linear) model $(A*B*C)$, when the highest interaction term $(A:B:C)$ is dropped, the response/raw residuals are exactly the same for different levels of two of the ...
10 views

### Unbiased proportion estimate for a 2-component Gaussian mixture model?

Suppose I have a 2-component Gaussian mixture model of dimension $p$, where each mixture has the same covariance matrix: $$\pi_1 \mathcal{N}(\mu_1, \Sigma) + \pi_0 \mathcal{N}(\mu_0, \Sigma)$$ ...
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### How to determine xdy dice roll from a sample?

I'm playing an RPG based on DnD xdy dice damage rolls, where x is the number of dice rolled and y is the number of sides on each die. So, normal double-sixes dice people are familiar with would be ...
12 views

### Plot Volume Under Surface in R for multinomial logistic model [on hold]

I have a model with a response variable with 3 categories and I want to run a multinomial logistic model. Is there a mode to plot a generalization of ROC in the simple logistic model, like the VUS ...
14 views

### Use of weights in PROC GLIMMIX

I am looking to implement a generalised linear mixed model in SAS using PROC GLIMMIX. The data is from a survey, and a single ...
15 views

### Is there a way to force seasonality from auto.arima [migrated]

With the forecast package, I have a time series that I would like ?auto.arima to automatically pick the orders but I would like ...
17 views

### Heterogeneity testing in logistic regression models

We ran 5 separate logistic regression models testing a set of independent variables on 5 different country-specific datasets. Our goal was to assess the relative contributions of known risk factors of ...
19 views

### How to calculate odds ratio per unit decrease of continuous variable

I have a logistic regression model obtained in R comparing association between two index diagnoses (0 or 1) with Age (continuous) + ...
20 views

### How to test the inclusion of a single random effect in glmer?

Suppose I have two models: m1=glm(DV~IVs) m2=glmer(DV~IVs+(1|Subject)) How can I test the inclusion of that random intercept in R? I know that I can't use ...
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### Is this following assumption of autocorrelation test right?

Basically I ran an autocorrelation test using first the d-watson test which resulted in an inconclusive result as it equaled du stat. Then I ran the durbin-watson alternative test which resulted in ...
36 views

### To call an api every minute from a URL, is R practically doable? Or would I need to do it in Python? [on hold]

I'm wondering if R is practical enough to call an api from a URL every minute and update the set of data. Would it be better use of my time to do learn and do it on Python instead of R? Thanks
10 views

### Metric vs feature

I'm dealing with a supervised N-way classification problem. Input is a feature matrix (NxM), and label vector (Nx1). Would there by any difference between the following in terms of accuracy: 1) Use ...
13 views

### Test for equal variance for 2-way ANOVA

Forgive a novice in statistics for asking a perhaps very simple question, but I am running a two-way ANOVA with unbalanced design and want to test for homoscedasticity using Levene. For a one-way ...
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### Linear AIgebraic interpretation of Standard Errors in ANOVA using R function

Background (can safely skip): I'm working towards some sort of computer illustration through a Monte Carlo, plotting, or linear algebra explanation, I don't know, of the effect of sample size on the ...
15 views

### How to perform a nested or hierarchical ordinal logistic regression in SPSS

I have one outcome/dependent variable that can be ordinal or nominal and 3 independent variables. I have learned so far how to perform ordinal and multinomial logistic regression in SPSS between a ...
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### How to calculate probability of a random sampling of a population

Let's say that I have a city for which I know the size in square miles and I want to know the probability of a random sample of individuals from that population living within a certain threshold of ...
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### Mahalanobis distance for highly multivariate random variable

I have to compute the Mahalanobis distance for a $10^6$ dimensional multivariate random variable. What is the best (and fastest) way to do this? I am currently taking cholesky decomposition of the ...
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### Mixed-effect models for repeated measures - problems with the “Significance level”

I am trying to fit a linear mixed-effect model to my dataset to see the relationship between a self-reported questionnaire and some physiological data. I've created a first model including all the ...
18 views

### ARMA errors and combining explanatory variables

Currently I'm working on forecasting the employee turnover of an organisation. To do this, I'm using a time series data of the employee turnover over the past 7 years, it is an annual data. To make a ...
8 views

### how to choose the test dataset and train dataset in link prediction [on hold]

hi i need to know how to split my dataset as test dataset and train dataset for doing the experiment of prediction links (i will apply common neighbors jaccard coeifficent ...) the dataset i have is ...