All Questions
210,293
questions
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23
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Strong consistency of kernel density estimator
I am studying the book Nonparametric and Semiparametric Models written by Wolfgang Hardle and have difficulty with the following exercise:
$\textbf{Exercise 3.13}$ Show that $\hat{f_h}^{(n)}(x) \...
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1
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0
answers
72
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How does Huber compute the $\operatorname{var}(s_n)/E[s_n]^2$ and $\operatorname{var}(d_n)/E[d_n]^2$?
(N.B. I am cross posting this question from math stackexchange since after
x days I have still not received any responses.)
How does Huber in book 'Robust statistical procedures' in chapter 1 compute ...
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0
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57
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What is the difference between a repeated cross-sectional survey design and a trend survey design?
Most of the references I have checked for repeated cross-sectional design and trend design (a type of longitudinal design) have said that they are one and the same. However, my professor says that ...
0
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0
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23
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BMA formula with BIC
I am interested in using Bayesian modele averaging as a selection creteria (BMA) vs AIC. I read that BMA is widely implemented in clustering models.
Suppose that we need to fit M models to a data and ...
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3
votes
1
answer
30
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Why is the space complexity of KNN $O(dN)$?
If you Google search the space complextiy of KNN, virtually all answers are saying that it costs $O(dN)$, where $d$ is the dimension of our data and $N$ is the number of our data.
But why?
I ...
- 1,373
0
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1
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48
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Binomial distribution with two probabilities
Here's the problem I have:
The probability that an apple is red is 80%.
The probability that a red apple is rotten is 10%.
If 10 apples are picked at random, what are the odds that half are red and ...
0
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0
answers
21
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Determine direction of bias with measurement error
We want to estimate the following population model:
$$y_i=\beta x_i+\epsilon_i$$
with $E[y_i]=E[x_i]=$ and $E[x_i\epsilon_i]=0$. We cannot observe $x_i$ directly, but we observe two variables $x_i^a$ ...
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0
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10
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Clustering of Variables around Latent Variables (CLV) over only qualitative data
I'm reaching out today because I have a concern regarding the clustering approach employed with the CLV method introduced by Vigneau and Qannari in 2003. I've noticed that this method is predominantly ...
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12
votes
7
answers
5k
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To a Bayesian, does a trick coin with two heads have 50% chance of flipping heads if they don't know that it has two heads?
And to expand on this idea, would uncertainty and complexity be the same thing to a Bayesian? For example, games with much randomness like poker and games that are more complexity based like chess -- ...
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2
votes
2
answers
327
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How could Lilliefors use Monte Carlo if the estimand is not distribution-free?
Lilliefors test is a well-known statistical test for normality. Its idea is based on the Kolmogorov-Smirnov test, except the CDF is replaced by the CDF of the normal distribution with $\mu, \sigma^2$ ...
- 235
0
votes
0
answers
12
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Incorrect reasoning on sampling from marginals
Suppose we want to sample $X$ from a density $p(x) = e^{f(x)}$. My thought was that maybe we can introduce an auxiliary variable $Y$ such that $p(y|x) \propto e^{-\|(x,y)\|^2/2 - f(x)}$. Then the ...
- 143
1
vote
1
answer
39
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Hypothesis testing in moderation analysis after Propensity Score Matching
I would like to perform a moderation analysis after Propensity Score Matching with a binary outcome model. I estimate a logistic regression outcome model (following this vignette). I am wondering, ...
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0
votes
0
answers
19
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How to know errorbars on accuracy to nonlinear fit: $A(1-\cos(x+\phi))$ with poisson noise?
I am trying to write some code that accurately estimates the parameters for the following function:
$$ Y = A(1-V \cos(X+\phi)) $$,
where this output data is poisson distributed.
To do this, I first ...
- 417
0
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0
answers
9
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Prediction when Target's lag values are part of Predictors
I'm using LGBM for regression, where the Target column's lagged values (7 columns for each lag day) are also used as predictors when training the model. Absence of the 7Day lag values severely ...
- 25
0
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0
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35
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Is predicting a coin flip 1:2 or 1:4 [closed]
My question actually applies to stock options "expected move" as published on trading platforms. The expected move calculation predicts wheather a stock price will move up a finite number of ...
0
votes
2
answers
33
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Question about 2 way mixed ANOVA when there is a significant between-group effect and it's relations to my hypothesis
I'm doing a research project for university and am trying to figure out how I should be interpreting my between-group effect in my mixed ANOVA.
My within-subjects variable is time and my between-group ...
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1
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0
answers
26
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How to analyze multivariate data that comes from a 2D design space?
I'm analyzing a set of biological samples. Each sample is linked to a specific carbon and nitrogen concentration, representing the 2D (experimental) design space I referenced in the title. I've ...
-1
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0
answers
15
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A random number generator has a 0.7% chance to land on prize A. Given a 90% confidence level, how many tries will it take to get prize A? [closed]
A random number generator has a 0.7% chance to land on prize A. Given a 90% confidence level, how many tries will it take to get prize A?
Please list the equations and approach used.
-1
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0
answers
11
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In the group sequential design how do we compute the test statistics for non-normal? [closed]
If the data doesn't follow, which test statistics could be used!
How will it affect inflate the type-1 error?
-1
votes
0
answers
8
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Clustering human evaluation
I am trying to figure out how can I evaluate my clustering methodology. I have gathered and processed some data such as:
I want to have several humans to put labels in column C, based on the top ...
- 555
3
votes
1
answer
37
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Why does nlme::fdHess return NaNs when evaluated at 0? [closed]
Why does the finite-differences gradient/hessian approximation nlme::fdHess return NaNs when seeking the gradient/hessian at 0?
<...
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-1
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0
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28
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Due to limited information How can I restructure my model to capture this relationship? [duplicate]
I created a model for prediction. The target data has a total of 4 classes (0-3), which makes my model completely ineffective. Due to limited information How can I restructure my model to capture this ...
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2
votes
1
answer
80
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E-commerce - Does higher delivery time lead to lower sales?
Question
I have a practical problem and am seeking guidance on how to use statistical methods to solve it.
I have an online store. The products in the online store have varying availability:
24 hours ...
- 121
1
vote
0
answers
48
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Average Marginal Effect interpretation for probit Model
I'd like to have your feedback about the interpretation of the Average Marginal Effect (AME) for a probit model. Suppose we have the following model
\begin{equation}
P(y=1|x)= \Phi(\beta_0 + \beta_1 ...
- 333
0
votes
0
answers
10
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Problem in understanding Brewster and Zidek technique to improve equivariant estimate [closed]
I am started working in estimation of parameters for several distribution. There I found that in most of recent papers they use Brewster and Zidek technique from paper "Improving on equivariant ...
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0
votes
2
answers
42
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What is the best test to use?
I am working on a project in my R introductory course but I really dont know what statistical test to use.
I got my data from the Malaria Atlas Project.
I want to know if the the Use of insecticide ...
- 1
0
votes
0
answers
15
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In Sklearn, based on scores, what model should I start tuning? [closed]
I am quite new in the Data Science world, so please be patient.
I am working on this Titanic classification project just to start practicing with machine learning https://www.kaggle.com/competitions/...
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0
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0
answers
17
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Multivariate normal distribution conditioning inequalities variable [closed]
The bivariate normal distribution X is as follows.
$X = (X_1, X_2)^\top \sim \mathcal{N}(\mu, \Sigma), ~ X \in \mathbb{R}^2 $
I want to know the exact distribution(pdf) $P(X | X_1 > X_2)$ in which ...
2
votes
0
answers
29
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Derivative-based effect size for Gaussian GAMs
It is often the realistic advice I have seen here that Gaussian GAMs are not regressions with which you can easily approximate an effect size for, as the effects are of course non-linear. However, we ...
- 6,011
2
votes
1
answer
38
views
Delong's test for comparing the significance difference of two AUC
I have done two prediction model in R as an example as below:
...
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0
votes
1
answer
23
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How to model observation error of multiple entries on a single Likert-type item?
This is a hypothetical problem for me at the moment because (1) I have no such data and (2) often software provides a forced choice in these cases so I doubt it would be a problem if I conducted a ...
- 6,988
0
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0
answers
15
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How to construct homogeneous subsets table for nonparametric tests?
Does post-hoc for friedman tests or nonparametric testshave like a homogeneous subset table from SPSS? Mean doesn't represent it well so I tried using median but my data was zero-inflated so the most ...
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0
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0
answers
8
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Can LayerNorm be used with feed forward neural networks? [closed]
FFN usually uses batch norm, but is there any reason why layernorm isn't used?
- 225
0
votes
1
answer
89
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Parametric vs Non-parametric test recommendation
What type of non-parametric test would be suitable for the dataset shown in the image:
The sample size is 200 each for both variables. The data value can vary from 0-4 for both variables. The ...
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0
votes
0
answers
8
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Is there a method bias when I prefer a specific post-hoc that shows a significance after significance in test of difference in groups?
I'm working to see if a machine does better than a worker in terms measurement (by having a measurement from an expert be the control). So my dataframe contains the Measurement Value, Measuring Device,...
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0
votes
0
answers
10
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Seeking Guidance to Ecological Models: Where to Start as a New Ecology Student [closed]
I am a new ecology student and am interested in the model part of ecology. I've used a few models, and while I can get results with them, I find that I don't really understand them. I don't know why ...
0
votes
0
answers
9
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Optimal formula to predict product when one of the components is certain
When an item is clicked, it generates revenue equal to the cost per click (CPC). As such, revenue = I(click) x CPC. I want to select the item with highest expected ...
0
votes
0
answers
22
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R deltaMethod(): evaluating a combination of parameters when one cell is empty [closed]
I'm running a linear regression with two categorical predictors and their interaction. One combination of levels does not occur in the data, and as expected, no parameter is estimated for it. I now ...
- 564
0
votes
0
answers
13
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Training problem in CNN model for image classification
I am training Cifar-10 dataset of 32 x 32 sized coloured images for image classification.
Here is the link/source to the dataset and its description: https://www.cs.toronto.edu/~kriz/cifar.html
The ...
0
votes
0
answers
11
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What does it mean when the Neural Network frequently has poor weight initialization?
I've been training a neural network to learn simple functions like addition. When I train this neural network from scratch, about half the time the neural network gets great accuracy, and the other ...
- 225
0
votes
0
answers
26
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PROC MIXED HELP [closed]
I am just starting out with PROC MIXED and unable to find help at my university, so hoping someone here can help!
I am setting up a model where my outcome (weight) is measured 3 times (baseline, 12m, ...
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1
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1
answer
34
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How to specify a linear mixed model (LMM) for a repeated measures design with two categorical predictors and one continuous?
I would appreciate some help figuring whether a linear mixed model (LMM) is a good choice for my data.
My experiment is a 3 (neurostimulation target) X 2 (task block) repeated measures design that ...
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1
vote
0
answers
27
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Neural network as alternative to conventional nonlinear regression?
Can I use the strength of neural networks for data analysis? Suppose I want to find a fit to a noisy sine curve $1 - V \sin(w \theta+ \phi)$ and I want to find an estimate for parameters V, $w$ and $\...
- 417
0
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0
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34
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Comparison of regression coefficients, same y but two different X versions
I've seen versions of this question but not specifically answering the question of a statistical test to compare the beta coefficients for two independent variables (x1, x2) but the same dependent ...
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0
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0
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6
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Model Selection on Coxme
I am building a "time to event" model using the coxme package in R. I have a lot of mixed effects (15) that I want to input into a global model and find the best fit for - is there a model ...
0
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0
answers
9
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Causal mediation analysis for time to event endpoints in randomized controlled trial data analysiscausal inference survival-analysis
I am struggling with a situation.
I have an RCT where there is an intermediate variable and an ultimate endpoint of survival (a time to event endpoint).
I want to establish that the intermediate ...
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0
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1
answer
17
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Best test for comparison of temporal counts
I have a data set of 182 concurrent count observations using two different methods and I was wondering what would be the best test to evaluate how closely related they are to each other.
My data set ...
3
votes
1
answer
39
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Validity of using non-time variable in survival analysis
I’ve conducted a time-to-event analysis (accelerated failure time) for a research project, looking at the effect of an intervention on the probability of needing a blood transfusion during surgery. ...
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1
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0
answers
23
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Weighted average of covariance matrixes
My issue is as follows:
In my model there are 4 different states, which each have a calculated probability of happening. I also have calculated covariance matrixes for my variables in each of these ...
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-1
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0
answers
20
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Wrong results for (pseudo)median on Wilcoxon paired test in R [closed]
I calculated results for the paired Wilcoxon test, one of which is (pseudo)median.
I tried to reproduce the computation of the ...
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