# All Questions

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3 views

### I would like to share our QC workshop materials with community

I would like to share our Lab's (University of Central Florida, Orlando, FL, US) traditional workshop materials. Here are papers on neural nets for solving differential equations and books. Look at ...
4 views

### Difficulty carrying out Automatic Portmanteau Test on R

I'm trying to replicate part of the empirical analysis of the following paper: https://www.tandfonline.com/doi/full/10.1080/23322039.2020.1719574#...
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### Which statistical tests to perform?

am working on an experiment with two treatments and a control and is replicated three times. Sampling was done at time intervals and at three different depths and i now have three sets of samples (...
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### Clark-Evans test results contradict to L function results

I have a data set including ~300 points and I would like to see if the point pattern tends to be clustered or not. To do this, I first performed the Clark-Evans test in R: ...
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### Help understand data structure and appropriate model (hierarchial data wtih repeated measures)

I have credit card transaction data, that I will describe with a relationship diagram. There are thousands of records, which are tied to a credit card, tied to a customer. Each customer can have 1-2 ...
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### How to compute sobol indices from a multi-variate regression model?

I have a dataset that consists of 300 input variables and 200 response variables. These response variables are basically a profile of 200 different values of the same response and they are 200 ...
5 views

### minimal detectable effect size in linear mixed model

I'm trying to find the minimum detectable effect size (MDES) given my sample, alpha (.05), and desired power (90%) in a linear mixed model setting. I'm using the ...
7 views

### Approximately how many data do we need to train a artificial neural network with 2000 parameters?

My approach is to think about ANN like a common statistical model. 2000 data for 2000 parameter is clearly not enough. However, if we got 10k data points then the training result might start to become ...
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### What does it mean to fail to reject in a one-sided hypothesis test?

Let's say we want to test the following hypotheses: $H_0: \mu = 0$ $H_1: \mu > 0$ for a random sample $\{X_1, \dots , X_n\}$ that is normally distributed $X_i \sim N(\mu, 25)$ (so variance ...
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### Is the determinant of the correlation matrix << 0.00001 necessarily a problem for PCA?

I am running PCA on my data and my KMO value > 0.80 and p-value of Bartlett's test of sphericity < 0.05. However, the determinant of the correlation matrix ( around 10^-30) is very close to zero....
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### Prove a result on expectation with 2 random variables

Part 1 I wish to show that: $$E(X)=E[(X|Y=y1)*Pr(Y=y1)+(X|Y=y2)*Pr(Y=y2)]$$ where the random variable Y can take 2 possible values. As many comments and answers have suggested, this may be technically ...
10 views

### Variance Formula

I have a question related to an equation that I once found but now I am unable to figure out what it is exactly used for. It is an equation for variance but I am unable to figure out what sort of ...
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### Why certain derivatives of the cost function are not averaged in a neural network?

I am going through Andrew Ng's Deep Learning Specialization and I'm in the third week of the first course. Right now, it's all about neural network backpropagation and I'm having trouble understanding ...
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### How can I prepare Ground Truth for dataset containing large number of images?

I've a large set of image data completely unlabeled(around 500 images,each containing around 80-100 objects to be labeled). I'm using an annotation tool to label objects in those images for preparing ...
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### Interpretation of coefficients in mixed-effects model with circular response?

I have a dataset from an experiment where wild ants were surveyed continuously for 24 hours under a number of temperature treatments (chambers). Whenever an ant was observed, the species of the ant ...
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### nonparametric vs. parametric

When deciding between applying parametric and nonparametric tests it is often recommended to look at the distribution of the data. Does this refer to the distribution of the data from (i) the ...
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### Paired t test: standard deviation of mean versus mean difference

I would be grateful if you could help me answering to a review I received: I have a sample that was evaluated in two different moments for the same outcome (n=80, normal distribution, Mean 1=272±20, ...
7 views

### Can I trick an ANN into learning individual values of an array from the average?

It is very easy to have an ANN that can compute the average of an input vector, but is it possible to have an ANN that can generate the output vector given just an average of the output vector as the ...
18 views

### Very high MCMC autocorrelation

I am using an adaptive MCMC (the covariance matrix updates at each step, and I also apply a scaling factor to keep the acceptance rate at a suitable level) scheme to determine the posterior ...
29 views

### What are constraints on including interactions into logistic regression?

I'm assessing effects of age, gender and speech style on the realization of linguistic forms. All the dependent and independent variables are binary categorical. My dataset: When I run logistic ...
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### How does the Bonferroni correction benefit from independent tests?

In section 2 of this PDF, it is stated that the Bonferroni correction "benefits" from the tests being independent, and that if tests are not independent, the Bonferroni correction could be ...
10 views

### Minimum Variance Unbiased Estimator of Poisson

Let $X1,X2,.....,Xn$ be iid Poisson random variables with unknown parameter $p>0$. Find the minimum variance unbiased estimator of $e^(-2p)$. I could find two estimators, one by the method of the ...
18 views

### Setting variance of an informative prior

I am creating a Bayesian Poisson Regression model and I have access to a dataset and a previous corresponding model. I want to use the previous model to create a prior that I will combine with the ...
34 views

### Does a paired t-test compare means?

The reason I ask is that I keep reading it compares means, yet everywhere people keep using box-plots for visualization, which seems fishy to me. In more detail I would like to know whether ...
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### multicollinearity and predictive power

In wikipedia it says ...
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### SPSS with R Plugin: Regular OLS-Regression vs. Robust Regression. Does R or R² Between The Two Models?

I have data that I want to evaluate with a regression analysis (N = 327, 2 metric predictors, 7 dummy predictors) Since I have non-normally distributed residuals and there is heteroskedasticity ...
9 views

### Object Scores in CATPCA

I've performed a CATPCA in SPSS and wish to use the components as explanatory variables in a logistic regression. I have finalised the CATPCA and am happy with the (5) principal components computed. ...
7 views

### Classification - compute residual error

I'm new to the field of time series forecasting and would like to know if what I think I'm doing makes sense. I'm looking to do a classification model to have a positive/negative indicator of power ...
12 views

### Probabilities_Logistic Regression [closed]

My question is more on conceptual level, suppose my data has 10 rows so with binominal logistic regression in place will I get, 10 probabilities corresponding to each row, they may tend to either y ...
12 views

### Account for autocorrelation without autoregressive model

I have a time series model that has seasonality (and therefore it has autocorrelated errors fitting an OLS model) - how can I account for autocorrelation without a complicated autoregressive model ...