# All Questions

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### What is the subject of statistics called if the subject is used to studying if the statistic formulated fit the actual data?

What is the subject of statistics called if the subject is used to studying if the statistic formulated fit the actual data?
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### How do I conduct model validation with glm models that have proportional response variable?

I would like to determine which environmental factors influence turtle nest survival. I ranked glm models with AIC using a step-wise procedure. The response variable is the proportion of eggs that ...
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### What is the minimum number of time periods for Granger causality test?

What is the minimum number of time periods required to reliably conduct a Granger causality test? I have a time series with only six data points, and I would like to know if it is possible to conduct ...
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### Error Output - Wrong model type for regression

I am trying to constructs an Learning Vector Quantization (LVQ) model. ...
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### False Positives, False negatives, true positives, true negatives

So I'm just starting to learn some proper statistics and recently learned about FP, FN, TP, TN. I'm a little confused as to how that works. Firstly lets say I have a way to predict whether a ...
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### How do Conditional Inference Trees do binary classification?

I am trying to learn about Conditional Inference Trees, and have been doing some very simple comparisons of the ctree() and rpart() functions in R. I have looked at the documentation for ctree(), but ...
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### Hierarchy predictive top down approach

I'm having a problem with using a hierarchical top down forecasting approach. According to my understanding, when I split an aggregated value on the levels below it, I have to know the percentages ...
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### 4 cases of Maximum Likelihood Estimation of Gaussian distribution parameters

Let $x_1,x_2,...,x_n$ some normally distributed observations. So $\vec{x}=\begin{bmatrix}x_1 & x_2 & ... & x_n\end{bmatrix}^{T}$ In the context of my research I am trying to estimate ...
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### How is bootstrapping used for machine learning?

How does one use bootstrapping in a machine learning context? My typical data analysis pipeline is Split data into 10 folds Train classifier with 9 folds Test classifier with remaining fold Repeat ...
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### Difference between latent and auxiliary variables

In a Gaussian mixture model, the labels assigned to the data points are often called auxiliary variables, whereas the cluster means and covariances are called latent variables. Since both types of ...
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### Get important features of n samples

Suppose I have a data frame of [n_samples, m_features] with the corresponding variances of the features [n_features]. The values in my data is between 0 and 1 so the question is: Is there any way to ...
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### cross correlation of partially correlated signals

I measure $x(t)$ and $y(t)$, two stationary random signals, and I want to find out if, and how much, they are correlated. What I'm doing is to plot the cross correlation ...
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### transitive property in statistical comparisons

I want to know if the exposure to a given dose of a toxic chemical alters the concentration of a given substance in blood in my animals. I make this super general, bear with me, because I think this ...
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### Distance between Vectors with Confidence Intervals

I have a machine learning application where I extract numerical features $a_{i1}, a_{i2}, \dots, a_{ik}$ for each object $a_i$ to study. Objects are then compared using standard euclidean distance. ...
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### Is polynomial regression restricted to linear models?

I'm wondering if polynomial regression extends to generalized linear models, so one could fit a model with a binomial, Poisson, gamma or other distributions? My question stems from a paper ...
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### Is NN overfitting if after a while validation error becomes constant?

Is neural network considered to be overfitting if after N iterations validation error stops improving and stays more or less constant, whilst training error keeps decreasing?
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### Results from logit model using BIOGEME unexpected

I am using BIOGEME to estimate the discrete choice model (choice is made among four alternative routes). I am having hard time with modeling using BIOGEME, and expecting help on this. I have dataset ...
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### How to analyze multivariable data (Normality not assumed)?

I have a table which looks like the table below. As you can see, I have two factors in the table. One factor which shows different interaction techniques and another shows different position of ...
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### How to determine if a single variable is significantly different than 0?

I am working with data that has been reduced to values falling between -1 and 1. The formula is, "(number in tube 1- number in tube 2)/ (the sum of numbers in both tubes). Example: Tube 1 = 5 worms, ...
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### R: Coping with bad model fit convergence during bootstrap

I'm running into trouble while checking the robustness of a GLM using the bootstrap procedures in R. Basically I want to check whether the estimated coefficient estimates of an existing GLM that I've ...
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### How can I do full Griffing diallel in Genstat over locations [on hold]

Genstat 17 is now doing Griffings diallel. However, how can I do the griffings diallel over locations. Thank you
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### ARMA-GARCH model selection / fit evaluation

I'm trying to fit an ARMA-GARCH model to a data set of FTSE 100 log returns. However, I'm not able to find a well-fitting model. Below are the ACF and PACF of the log return series and the ACF of the ...
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### Dictionary for common technical terms (embedded systems) [on hold]

I am looking for a dictionary for microcontroller and embedded systems for the purpose of text mining and natural language processing in technical documents. In the optimal case it would be structured ...
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### $\chi^2$ tabulated value

I noticed that the critical $\chi^2$ value increases as the degrees of freedom increase in a $\chi^2$ table. Why is that?
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### Collapse duplicate rows by median value in R [migrated]

I have a date frame with two columns. I would like to remove rows where there are duplicate entries in the first column. however I would like to select a specific row to remain based on the value of ...
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### How to select a subset of variables from a large dimensional dataset for Gaussian Process Regression?

I am currently working on GPR(gaussian process regression) on a large dimensional input dataset(around 300). I am pretty sure that some of these variables have weak correlation with target output. If ...
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### ANOVA test mean against predefined constant

How can I calculate the p-value (statistical significance) if my hypothesis asks for specific mean values? I suppose this can be somehow calculated using ANOVA, but I could only find examples where ...
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### Continuous Independence Test using only sufficient statistics

does anybody know a way to test wether two continuous variables X and Y are independent only using their sufficient statistics? The work I have seen so far was assuming that N values of variable X and ...
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### Univariate Linear regression [on hold]

I have only one predicator variable but I have it in 2 different times (week 18 and week 32) in a categorical form ( no, yes occasionally, yes mostly), and my outcome is a numerical variable. is it ...
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### Statistical Significance

Our teacher told us If a test is rejected at 1% level of significance , then it will be rejected at 5% , 10% level of significance . I don't understand how does the rejection at 1% level of ...
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### Multiple response question with copied observations

For an analysis with the answers of a multiple response question submitted by respondents as the dependent variable, I was thinking of using duplicate observations. So e.g. if a respondent submitted ...
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### How can weighted K-NN decrease accuracy?

I have heard that weighted K-NN improves the accuracy.But in my case, the accuracy decreases.Can anyone suggest why there is a decrease in accuracy?
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### How to get LDA projection matrix in Matlab

I didn't find anything about projection matrix in fitcdiscr help page. Is it possible to extract projection matrix from a model? If not, do you know some matlab LDA implementation that outputs this ...
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### Initialization af biases in CNN

I just found the following quote in ImageNet Classification with Deep Convolutional Neural Networks, one of the most important papers within deep learning. It states that some neuron biases should be ...
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### Combining confidence intervals from several regression point estimates

I have 13 point predictions from 13 independent linear regressions, each prediction with a 95% confidence interval. I want to sum the 13 predictions and calculate the 95%CI for the summed value. ...
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### Properly calculate mean and SE for meta-analysis

I want to perform a meta-analysis, for which I have data from 30 different experiments, each of them with two different treatments. I have three different types experiments based on how the data are ...
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### Confirming calculations with simulations?

This question may be a little abstract, but I would like to understand how to develop a mentality towards performing statistical simulations. For example: If I have a normal distribution, and I ...
I need to add a series of numbers with asymmetric standard deviations, such as $$5_{-2}^{+1} \,+ \,3_{-3}^{+1}.$$ Although I know it's common to add the upper errors ($\sigma_{\scriptsize{+}}$) and ...