# All Questions

138,816 questions
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### 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 ...
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### survival probability to proportional hazard ratios in r

I am using Cox proportional hazard regression to determine the association between physical behaviors (physical activity, sedentary behavior, and sleep) and mortality. to elaborate on these results, I ...
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### Estimation and detection in communication problem?

I just want to get clear conceptually about the difference between detection and estimation in terms of a communication problem. Suppose I have a source and a destination. The source transmits binary ...
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### What are properties of copula functions in simple words?

I read a lot about copula functions lately, and I think I understand the basic concept quite well. But I still have trouble understanding this summary of copula properties: Can someone help me to ...
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### What to do if random forest still overfit after grid tuning?

I have a random forest and an ols regression. Both models i want use for an out of sample prediction. Before tuning the parameters of the random forest the default settings of the random forest yield ...
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### Variance of a linear (and/or nonlinear) combination of an integral function (i.e., related to stochastic)

Let $I(t) = \int_{-T}^T e^{10\pi t} \{a_1X_1(t)X_2(t) + a_2X_3(t) + \dots \} dt$, where $a_i$ are constants and $X_i$ are independent random (Gaussian) variables. Is the following relation true? (or ...
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### Proof of Rao Blackwellization

I am reading this classic paper (Information and the Accuracy Attainable in the Estimation of Statistical Parameters) by CR Rao where he introduces the idea of minimizing the variance of an unbiased ...
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### mutation difference

I am hematology/oncology physician. i am doing project in CNS lymphoma. i have a question about the best method to calculate if there is any statistical difference in mutation frequencies between 2 ...
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### Explaining the regression model

Given the model: Y = a + β1 + β2 + β3 cos (∠) +β4 sin (∠) +errors resulting from a negative binormial regression, how can I explain the section of β3 cos (∠) +β4 sin (∠) given that they are the two ...
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### Oversampling impact on semi-supervised multi-label 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 ...
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### Transforming a distribution into another one?

Say I have two vectors X1 and X2, and they form two distributions. Is there any way to transform X1 so after the transformation the new_X1 will have a similar ...
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### Why need wald test ( a squared version of t test ) when we already have t test?

It seems to me that they are basically calculate the same thing. Since we already have t test, why do we need a squared version (wald test)? Does wald test have its own advantage? For example in Cox ...
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### Recursive partitioning tree vs neural network model

I hope this question helps shed some light on trees vs neural models. I recently came across a model tree, or a recursive partitioning model. It is basically a decision tree that has linear regression ...
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### What is the relationship between minimizing prediciton error versus parameter estimation error?

With the advent of statistical learning techniques, people are talking a lot about prediction error, while in classical statistics, one is focusing on parameter estimation error. What is the ...
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### Is Dynamic Time Warping Affected by the Length of Time Series

I am trying to use DTW to compare pairs of EEG signals over different events. After I computed DTW distance for each event; I noticed that the longer the event is, the larger the DTW distance becomes. ...
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### How to test whether birds spend more time in sepcific areas along a time-segmented track?

I have geolocation data on birds with 1 position per day (latitude + longitude) plus I have for each day, a corresponding binary time series that takes values 0 or 1. There is periods of minimum 10 ...
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### I'm learning R, I need help with some questions [on hold]

If I have p=0.02 The probability that the third success is between try 20 and 25 is: The probability that the third success will come after the 20th attempt is: The probability that the third success ...