# All Questions

140,566 questions
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### Convolutional neural network & recurrent neural network vs. dense feedforward networks

What are the benefits of convolutional neural networks structures and recurrent neural network structures compared to the dense feedforward network when there would be enough computing power to ...
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### Odds of an event happening over a long period of time

If there is a fluctuating chance of rain throughout the day how do you calculate the chance that it will rain at some point throughout the day? For example, tomorrow there is a six hour period with ...
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### about the sample size calculation of three or four groups in survival analysis

I have a question about the sample size calculation of three or four groups in survival analysis. Do you know some package in R, Stata, or other resources?
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### Calculating test group sizes for Statistical Significance in Subject Line split Testing

Hoping for some insight or advise on the calculating ideal test group sizes in this the following scenario: Say I have a million contacts that are delivered an email campaign I want to implement a ...
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### In linear regression, what would it do to center the label?

In this question linked below, it was addressed why we would center the features in linear regression. When conducting multiple regression, when should you center your predictor variables & when ...
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### Multiple priors in Bayesian estimation

Typical Bayesian estimation equation is: Estimate = ( SampleSize * SampleEstimate + PrioriEstimateWeight * PrioriEstimate) / ( SampleSize + PrioriEstimateWeight ) Typically, the PrioriEstimate is ...
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### How likely is sample A and sample B is from distribution C? [on hold]

Let's say I have a sample A: [0,0,0,1] and another sample B: [2,0,5,10,100,3,2,6] I would like to know the probability that A and B are both picked from the same population C. I tried applying a ...
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### Endogeneity bias

For my dissertation, I am trying to determine whether chosen 'sentiment measure' have predictive power for stock returns(S&P 500). These sentiment measures consists of LN VIX for example ( change ...
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### What are some good strategies for improving a classifier that works well on most of the classes but confuses 2 of them?

I'm having a classifier that tries to classify 5 different classes from a data set. It works pretty well in general, and when I'm plotting the confusion matrix almost all misses are 0, 1 or 2 max 3 ...
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### What statistical technique could be used to extrapolate CO2 data

I am new to statistics but scraped data from NOAA's web site to plot CO2 level vs time. Is there a good statistical technique to extrapolate past limit of data X axis to near future like 2050? One ...
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### Estimate for the standard error of the probability of a residual lifetime

Suppose that we estimate the survival function using the Kaplan-Meier estimator. Based on that KM-curve $\hat{S}(\cdot)$, one can then estimate the probability that the residual lifetime is larger ...
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### Bootstrap Prediction Bands for Linear Regression (in R) [on hold]

I am looking for a way to implement non-parametric bootstrap to prediction bands around my regression line and confidence bands for my linear regression model. I am, however, new to bootstrap, ...
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### Why does kmeans after SVD result in ideal clusters

I am clustering tweets which are related to eye fashion and they are extracted using keywords like mascara, eyeliner, eyeshadow, etc from twitter. I constructed a Tf-idf matrix (tweets x words) ...
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### How do I run a multiple-polynomial regression using percentile rank data? [on hold]

For each x variable, I have 500 columns of specific data where each column is the percentile rank of a given column in regards to the other 499 columns. However, since I have hundreds of x variables,...
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### Kernel-weighted local polynomial smoothing in Python? (Replicating Stata/R functionality) [on hold]

I am currently using LPOLY from Stata (https://www.stata.com/manuals13/rlpoly.pdf) to create a smooth curve between different Political Pollsters: ...
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### correlation coefficient bivariate normally distributed [duplicate]

Suppose that X,Y and X,Z are bivariate normally distributed. We have $E(X)=0, Var(X)=10$, $E(Y)=0, Var(Y)=6$ and $ρ_{xy}=0.87$ Moreover, $E(X)=0, Var(X)=10$, $E(Z)=0, Var(Z)=4$ and $ρ_{xz}=0.87$ ...
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### Non-negativity of interaction information for special trivariate case

I am trying to prove that if a discrete trivariate distribution $P(X_1, X_2, Y)$ satisfies $$P(X_1=x_1, X_2=x_2, Y=y) = \min( P(X_1=x_1,Y=y), P(X_2=x_2,Y=y) )$$ for all $x_1, x_2, y$ then the co-...
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### Binomial distribution - Variance (Experimental vs theoretical)

Just been experimenting with creating a simulation for the binomial distribution. I've made an applet in Geogebra that generates the histogram, mean of the experimental data, the variance of the ...
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### What is $X$ in the fundamental equation of factor analysis?

Mulaik (2009) p135-136 writes that Let Y be an $n \times 1$ random vector of random variables whose variables are the observed random variables $Y_{1}, ... , Y_{n}$. Assume that $E(Y) = 0$ and ...
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### How to analyze the relationship between two variables in a time sequence

I have a question about how to analyze the relationship between two variables in a time sequence. It is an eye-tracking experiment. I recruited two separate groups of Mandarin speakers to describe ...
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### Frank-Wolfe vs Matching Pursuit

Which are the differences between (Orthogonal) Matching Pursuit and Frank-Wolfe algorithm? Are both applicable to the same constrained convex optimization problem?
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### Does this notation in the context of reinforcement learning have an unambiguous measure-theoretic interpretation?

In the context of reinforcement learning, I have seen the formula $$V^\pi(s)=\mathbb E_{\tau \sim \pi}[R(\tau)|s_0=s]$$ and $$V^\pi(s)=\mathbb E_{a\sim \pi}[Q^\pi(s,a)]$$ Does this notation have ...
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### Can the calculation of entropy be generalized to an infinite series?

For a finite problem size $n$, it's straightforward to calculate the entropy of a random variable $X_n$ for the function I'm interested in. With the particular kinds of functions that I'm studying, ...
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### polynomial contrasts- bayesian analysis [on hold]

I need to check a cubic trend (polynomial contrasts) using Bayesian analysis. I tried to find solutions on line and could not find it. can i use R for that, and how ?
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### 2D max pool gradient propagation

I am trying to understand gradient propagation for a 2D max pooling operation when there is multiple filters for each position in the 2D grid (i.e. size = $b\times2\times2\times d$, where $b$ is ...
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### What are the outputs of the inspect for SEM in lavaan?

According to the tutorial, inspect "returns a list of the model matrices that are used internally to represent the model". But what exactly are those matrices? Code: ...
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### Fast Non-uniform DFT in R

So, if I want to compute discrete Fourier transform (DFT) in R, I can create my own functions like so: ...
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### dispersiontest() estimates dispersion too small

I am using dispersiontest(fit, trafo=2) from the AER package in R to see if my data is overdispersed and what the dispersion parameter $\alpha$ is. Since I use <...
161 views

### Wilcoxon signed rank test – critical value for n>50

I have seen that someone has asked a similar question a few years ago, but unfortunately the answer is not helpful. I am in the process of estimating a Wilcoxon signed rank test with a n=63 by hand. ...
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### 'aqmm' - sample R code & output interpretation? [on hold]

Does anyone have sample R codes and outputs for 'aqmm' (additive quantile mixed model)? This would help me visualize how to set up my model and interpret outputs. I'm trying to build an additive ...
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### How to check if means and variances are normally distributed?

From here I read that The t-test assumes that the means of the different samples are normally distributed; it does not assume that the population is normally distributed. By the central limit ...
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### Should I average data sets and calculate single parameter or average individual data set's parameters?

I am interested in calculating oxidation reaction kinetics parameters of a material at a particular temperature. Essentially I have a curve of data (mass change) vs. time for the particular ...