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Minimum population size for a comparison of treatments

Is there a rule for minimum population size for horticultural experiments and trials? For example, growing a plant variety in 5 different soil types in 5 different locations. My apologies if my ...
2
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1answer
9 views

Kolmogorov-Smirnov (ks_2samp) p-value not as expected - Wrong test or understanding?

Context I am using scipy's ks_samp in order to apply the Kolmogorov-Smirnov-test. The data I use is twofold: I have a dataset ...
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0answers
7 views

How can you measure probability with a regression model?

Classifier-based machine learning models have a corresponding "confidence" associated with each prediction. How can you get a confidence measure for a regression model?
4
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1answer
18 views

When rolling a dice N times, what is the probability of a symbol X appearing before Y?

When rolling a dice N times, what is the probability of a symbol X appearing before symbol Y? So a valid state is when lowest index of X is smaller than the biggest index of Y. For example N = 5, X ...
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0answers
7 views

Long-run covariance matrix estimators with Ledoit-Wolf (2004) shrinkage; what methods exist?

Ledoit and Wolf ("A Well-Conditioned Estimator for Large-Dimensional Covariance Matrices", 2004) proposed an estimator for the covariance matrix of a data set, $S^* = p I_d + (1 - p) \hat{S}$ with $p \...
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3 views

Bayesian regression not normal

Let's say Im trying to do a bayesian linear regression and I have some strong prior on the parameters x1,...,xn. However, after collecting my data I can clearly see the residuals are not normally ...
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0answers
4 views

Resampling methods or statistical tests for variables that comprise dependent and independent observations

I am currently working with a dataset that comprises measurements of multiple participants on two variables. I'd like to test the mean difference between both variables on statistical significance. ...
0
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0answers
6 views

Interactions between categorical and continuous independent variables

Im going to investigate if a disease have a negative impact on the development of children. The disease is the independent variable with additionally 10 confounders. Do I have to check for ...
1
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1answer
8 views

geeglm y ~ x1 + I(x^2)

In glm if a model is specified as ...
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0answers
8 views

Do these two Bellman equations express the same idea?

I am currently trying to wrap my head around the Bellman equation and found the following two definitions. The first one is taken from cs229 Stanford - link to the sources is avaiable below. The ...
4
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2answers
42 views

Do Bayesian credible intervals treat the estimated parameter as a random variable?

I read the following paragraph on Wikipedia recently: Bayesian intervals treat their bounds as fixed and the estimated parameter as a random variable, whereas frequentist confidence intervals treat ...
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0answers
5 views

SEM output with a DWLS est - non normal distributed variables: feedback, possible overfitting?

I have a sem model with non-normal distributed indicators measured with Likert-scale (7 points - agreement). I have 4 LVs and 1 observed (N=287, data collection still in progress). As variables in my ...
5
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1answer
30 views

The No-Free-Lunch Theorem and K-NN consistency

In computational learning, The NFL theorem states that there is no universal learner. For every learning algorithm , there is a distribution that causes the learner output a hypotesis with a large ...
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0answers
14 views

Isolation Forest and average/expected depth formula

The Isolation Forest algorithm (Liu, Fei Tony, Kai Ming Ting, and Zhi-Hua Zhou. "Isolation forest." 2008 Eighth IEEE International Conference on Data Mining. IEEE, 2008. - link: https://cs.nju.edu.cn/...
2
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1answer
18 views

What are some of the most correct/accepted ways to tune and compare different models in an academic context?

Those days, I have been reviewing different academic papers which mainly compare the performance of different machine learning methods on a particular problem. And I was surprised by the variety of ...
2
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3answers
35 views

“Magical” variance reduction problem

I recently came across this toy problem: You have two sticks of unknown lengths $a>b$ and a measuring device with constant variance $1$ that you can only use twice. How can you construct ...
1
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1answer
13 views

hyper parameter tuning AFTER Nested cross-validation

I have read very well the awesome answers and suggestions by @cbeleites and @Dikran Marsupial here for nested CV but I am still confused about something: Basically now I understand that nested CV is ...
0
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0answers
5 views

Can three-level meta analysis be random-effects model and/or fixed effects model?

I am learning three-level meta-analysis and trying to deeply understand how this new relatively new approach fits into the more commonly used general meta-analysis (...
0
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0answers
6 views

Within subjects error bars in GLM [on hold]

My question is about calculating the within subject error bars in data I analyzed using a generalized mixed model. The dependent measure is accuracy (binary - correct/incorrect), and the fixed factors ...
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0answers
6 views

Relationship between sub sample and full sample coefficients

Consider a linear regression model: $$ y_{i}=\boldsymbol{x_{i}'\beta}+\epsilon_{i} $$ where $\boldsymbol{x_{i}'}$ is a column vector of covariates and $i$ is individual for a total of $N$ individual. ...
1
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1answer
16 views

Interpreting predictive models in the presence of omitted variables

Suppose the best predictive model from a set of possible models is a univariable model, due to lots of moderate correlations with other variables for example. However, if I use this model for ...
0
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0answers
12 views

When developing the Yule-Walker equations, why can we assume $E(X_{t-k} \cdot Z_t) = 0$

I have a AR(1) process $X_t = 0.4X_{t-1} + Z_t$. I want to derive the Yule-Walker equation. I multiplied by $X_{t-k}$, took the expectation of both sides, and got: $$E(X_{t-k}X_t) = 0.4E(X_{t-k}X_{t-...
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0answers
10 views

Why does the Yule-Walker equation for AR(1) only hold for $k \ge 1$?

I have a AR(1) process $X_t = 0.4X_{t-1} + Z_t$. I multiplied by $X_{t-k}$, took the expectation of both sides, divided by the variance (which I assume is stationary), and got the Yule-Walker equation:...
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0answers
8 views

Plotting simple slopes in RMANOVA?

I have an experiment that measures behavior across 4 blocks. I have a between-subjects continuous physiological variable that interacts with this block effect: physiology x quadratic block effect. I ...
0
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1answer
24 views

Question about PDF's for Random Variables

"Suppose we have the random sample of n independent and identically distributed random variables with a normal distribution. The probability density function of each Xi is..." If our variable was e....
0
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0answers
8 views

How to tackle package building problem in compiling R [on hold]

My question is about how to compile R on windows. I tried compiling R 3.6.1 with OpenBLAS 0.3.7 on windows 10 x64 using Rtools 3.5, but the process stopped due to a mistake: ...
1
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1answer
9 views

How do i re-train a final model after using oversampling?

I am a bit puzzled about the process of experimenting with a model and oversampling and then translating it to the final version of the model that will be used: I oversample the data (only the ...
2
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0answers
7 views

Learning a target feature from data

I have a dataset of customers (infos about them, as well as their buying behavior) to whom ads are sent regularly. How can I design a target feature that will result in a good model that predicts when ...
1
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1answer
33 views

What does Deviance mean in lmer

Probably a rather silly question, but I would like to have a clear explanation of what deviance in linear mixed models (using lmer) is. For instance, how do I interpret it along AIC, BIC, and LOgLik ...
6
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2answers
127 views

Can RMSE and MAE have the same value?

I am implementing cross validation and calculating error metrics such as RMSE, $R^2$, MAE, MSE, etc. Can RMSE and MAE have the same value?
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0answers
11 views

Why is the rank of a matrix called rank? Is there an explanation for how this property is named? [on hold]

Is there an explanation for how this property is named?
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0answers
31 views

Estimating the range of $1$'s in an array of $0$'s and $1$'s

I have a large array $A$ that contains something like $[0..1..0..]$. It has a continuous range of $0$'s, followed by a range of $1$'s, and then another range of $0$'s. This array is large and access ...
2
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1answer
9 views

Output dimension of convolutional layer - where did color dimension go?

I'm working with a Convolutional Neural Network in Matlab, and I'm struggling to understand the output dimensionality of a convolutional layer. The input is an image: ...
2
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0answers
11 views

How to specify latent variables for SEM with lavaan [on hold]

I would like to use lavaan for SEM. Specifically I want to use the paper: "Original Article Maximum Likelihood for Cross-lagged Panel Models with Fixed Effects", by Paul D. Allison, Richard Williams, ...
1
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1answer
16 views

Is covariate significant in logistic regression

Im going to investigate if a disease have a negative impact on the development of children. The disease is the independent variable with additionally confounders. Tests from the study have shown ...
0
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0answers
4 views

The amount of variables used in SEM models with lavaan

I would like to use lavaan for SEM. I am have however struggling to get things running (I went through al the examples, but they always deal with these perfect datasets). The only thing that has ...
1
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0answers
4 views

Creating a covariance matrix for SEM from lavaan

I would like to use lavaan for SEM. Specifically I want to use the paper: "Original Article Maximum Likelihood for Cross-lagged Panel Models with Fixed Effects", by Paul D. Allison, Richard Williams, ...
1
vote
2answers
19 views

Power Analysis in G-Power - Mixed Model Anova

I'm an honours student in psychology doing some data analysis at the moment. My research project is coming to a close for data collection, and it seems like we won't reach our initial goal. I decided ...
1
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0answers
6 views

How to interpret the result from local sensitivity analysis?

I am currently doing local sensitivity analysis on a model that has 40 input parameters. I varied the base case value by 10% within the range of [-1, 1]. While doing so the average change (here, I ...
2
votes
1answer
22 views

When are biased estimators with lower MSE preferred?

From wikipedia https://en.wikipedia.org/wiki/Bias_of_an_estimator : because a biased estimator gives a lower value of some loss function (particularly mean squared error) compared with unbiased ...
2
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0answers
11 views

Reference thesis for outliers in likert scale data

I have a data set that was collected in form of a liker scale through questioners. Now, i am trying to eliminate or identify outliers in my data. By far, from all that i have been able to search, ...
4
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0answers
337 views

Are there highly cited papers on statistics that have actually spread statistical falsehoods?

There are obviously many ways to abuse statistical methods. Do you know of any examples of statistical falsehoods that were first published as explicit advice (e.g. "you should use this method to ...")...
2
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1answer
27 views

How do I interpret the random variable $X_i$?

"Suppose we have a random sample of n independent and identically distributed random variables $X_i$" Hi, I am new to statistics. I am confused as to what $X_i$ represents. Are the $X_i$'s different ...
0
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0answers
20 views

Events per variable in LASSO regression

I'm using LASSO regression to select genetic variables that predict time to an event (using glmnet with Cox in R). I have approximately 300 predictors and 1,000 events. I'd like to keep my events per ...
1
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0answers
8 views

Variance of Random Vector in the Circular Orthogonal Ensemble

Let $x$ be a (uniformly) randomly chosen column of a random orthogonal matrix (of size $K$ x $K$) distributed according to Haar measure. What is $\mathbb{E}[x]$, $\mathbb{E}[x x^T]$, $Cov(x, x)$, and $...
0
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0answers
9 views

Approximation for the sampling error of the number of positive cases in a Bernoulli trial

Reading the book "Energy for Future Presidents" I found a way of approximating the binomial proportion sampling error which I never saw before, and I would like to know if my derivation is correct. ...
0
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0answers
6 views

What does the graph for a convolutional layer look like?

I like to draw out computational graphs when I work on small assignments for computing gradients etc. and was wondering what the graph for a convolutional layer would look like? I can't seem to find ...
1
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0answers
12 views

In this concrete example of applying sklearn knn (with kd_tree) on Iris Data Set, how many partitions are there?

The k-nearest neighbors algorithm (k-NN) is a non-parametric method used for classification and regression. In both cases, the input consists of the k closest training examples in the ...
1
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0answers
9 views

How can we apply the rule of stationary distribution to the continuous case of Markov chain?

If the Markov chain converged then $$\pi = Q* \pi$$where $ \pi$ is the posterior distribution and $Q$ is the transition distribution(it's a matrix in the discrete case). I tried to apply that on the ...
1
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0answers
12 views

Multivariate stationarity/cointegration test

Am I right to say that for multivariate time series, we can't use normal stationary test like Dickey–Fuller test and we need to use cointegration Test like Johansen? Or this is not true in general?

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