# All Questions

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22 views

### Comparing one value to mean or median of a group

I have very limited statistical knowledge or experience, so I am looking for some guidance on my approach for statistical analysis. I have a group of 60 values. I am looking to compare the last value ...
28 views

### What is the algorithm behind the 'distance' option of 'RadiusNeighborsClassifier' of sklearn? [closed]

In scikit-learn version 1.4.2, I am testing RadiusNeighborsClassifier, and I found the option weights='distance' greatly ...
8 views

### Why does increasing length scale prevent kernelized Perceptron with RBF from achieving a perfect fit?

My question is nominally about the Perceptron algorithm but is an attempt to explore what keeps kernel models with infinite dimensional feature spaces from becoming overfit. Imagine I am using a ...
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373 views

### The rationale for when significance or null hypothesis testing is needed

Why do people sometimes claim that an effect is so huge and "obvious" that it does not warrant any inferential statistics calculation, even though the sample size is not large? This is ...
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9 views

### Timepoint lsmeans post-hoc mean comparisons

Can anyone suggest which is the most appropriate test? I have changes from baseline (4 timepoints including baseline) in the Y axis and the timepoints in the X axis, 4 treatments. I want to see, if ...
17 views

### Is there a way to judge two people fairly when we have more samples of one person more than the other? [closed]

I have more samples of one person's performance than the other. should I just remove the extra samples?
32 views

### Standard error and confidence intervals [duplicate]

About theoretical concepts... We use confidence intervals to do an inference to extrapolate results from study to similar sample. Is this true? Which is the difference between a confidence interval, ...
24 views

### Standard error of mean with varying replicates for batches

I have three batches of simulations and I calculate a specific property from these (not important for the question). I want to calculate combined SEM for these three batches Batch | #samples | ...
1 vote
15 views

### How Does Serial Correlation Cause OLS to remain unbiased (even in cross -sectional data)

In order for the coefficient estimators to remain unbiased in OLS, the conditional expectation of errors given the regressors needs to be zero, $E(u_i |x_i )=0$. However, if we have serial correlation ...
13 views

### Relationship between A/B testing and testing for (First-Order) stochastic dominance

Is there a relationship between A/B testing https://en.m.wikipedia.org/wiki/A/B_testing and stochastic dominance, e.g. First-Order stochastic dominance https://en.m.wikipedia.org/wiki/...
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14 views

### HAC for plm object in r [closed]

I want to estimate a fixed effects model (with both country- and year fixed effects) and ADDITIONALLY apply HAC standard errors. Although I didn't get any error message after running the following ...
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8 views

### Equality arising from coinciding of $R^2$ with slope of regression of predicted vs observed values

If I am able to interpret this correctly, then in the accepted answer to Does the slope of a regression between observed and predicted values always equal the $R^2$ of the original model? it is proven ...
20 views

### How can I integrate time in my Implicit Feedback dataset?

I'm working on a recommendation system based on Collaborative Filtering. Specifically, I've been looking at models such as NCF (Neural Collaborative Filtering) and SAR (Simple Algorithm for ...
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13 views

### Identical SE values for different groups using emtrends [closed]

I'm using emtrends to extract slopes and do pairwise comparisons between the groups of my independent variable, controlled for the other variables in the model. ...
• 101
162 views

### Why are 1/SE or 1/variance commonly used as weights in regressions?

I'm trying to do a meta-analysis for the first time, comparing measurements of a simple experiment treatment against a control in a variety of species. I started by fitting a mixed-effects model to ...
• 18.7k
15 views

### Identical SE values for different groups using emtrends

I'm using emtrends to extract slopes and do pairwise comparisons between the groups of my independent variable, controlled for the other variables in the model. ...
• 101
32 views

### Reason for high MSE and negative R square value

I am getting really high MSE and negative R square value. Dataset: https://docs.google.com/spreadsheets/d/1moTZS_LgOn6d74NC44i9lVcWchj-abVx/edit?usp=sharing&ouid=100514649347129021200&rtpof=...
6 views

### Behavior of clustered SEs for cross-level interaction with a 0 cell in fixest

I am using fixest in R for fixed effects logistic regression with clustered SEs. I am not able to share my data but hope I can explain the question well. I have 11 clusters with between 29 and 493 ...
1 vote
66 views

### ANCOVA or MODERATION?

I'm struggling with the statistics for a question I'm collecting data to answer. My paper is about whether different meditation types can increase happiness when controlling for meaning in life. There ...
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1 vote
80 views

### How to model a controlled experiment (three time points, two groups) in lme4?

We conducted a behavior change field experiment using the following variables: Three time points (T0, T1, T2) Two groups (intervention vs. control) Individual ID Workshop ID The intervention was ...
68 views

### Handling the situation: (x ~ y) == (y ~ x)

If fitting the following two models, using linear regression, produces coefficients that are essentially the same, what is the appropriate modelling technique to use? ...
• 127
33 views

### "Repeated measurement test" data input [closed]

everyone! I just started evolving with SPSS a few weeks ago. Let’s say I want to do a statistical test to check the efficiency of 4 different pesticides over 5 weeks (the first week is the control). ...
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17 views

### Re-calculate accuracy,precision and recall after treatment effect in a model

Working in a churn-prediction model where the goal is to detect the players that have a high chance to churn from the site and send those players an offer to keep them in site. In the initial training ...
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16 views

### Understanding softmax as an activation function, and sparsity in data and gradients

I’m working on a project that includes a probabilistic model that uses one hots, and also occasionally partially freezes weights or zeros gradients to specific regions of the weights. In some parts of ...
6 views

### Gaussian Field of Poisson distributed Random Variables

Can it be that the spatial process is a Gaussian field even if the observations are Poisson distributed? How does any finite combination of them follow a multivariate normal distribution?
30 views

### Analysis of research with small sample size, nesting and many outcomes [closed]

I am tasked with analysing the results of a study where 6 groups of 6 animals were included (one was positive and one was a negative control, 4 treatment groups), and assessed across 4 main categories ...
66 views
+50

### Estimating Smooth Density Field from Limited Sampled Data

I want to estimate a “density field”, specifically $P(y|x, m)$, for binary labels $y$ associated with 2D points characterized by spatial coordinates $m$ and additional spatio-temporal features $x$. ...
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9 views

### Linear Probability Model in a hazard framework (right censored data) [closed]

As I am working on a paper, I need to run a Linear Probability Model (LPM) in a Hazard framework. I have almost 1 million mortgage loan data with their characteristics and monthly payment performances ...
20 views

### What is proposal distribution in Importance sampling

I want to learn importance sampling using a simple example. Consider the following example code which implement importance sampling using python for a simple Bayesian network. I've read that we fix ...
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68 views

### Can I use Tanh before softmax?

I am researching the use of neural networks for binary classification tasks of financial data. The output result is two-dimensional, such as [[0.5,0.5], [0.1,09]]. In the case of only 2000 small ...
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15 views

### When we talk about the Likelihood in general ... Are we talking about a "Joint Likelihood" or "Conditional Likelihood"? [duplicate]

I am confused about this. Suppose we collect some data and believe it came from a Normal Distribution. To estimate parameters (mu, sigma) of this Normal Distribution we create a Likelihood Function ...
51 views

### Probability Intervals with Machine Learning [closed]

Goal: Find the interval where a probability really lies with [x]% confidence. Let's start with a non-predictive experiment. A coin toss. Heads or tails. We already know that in a fair game, the ...
13 views

### Combining Variation and Uncertainty from Replicate measurements

I have 3 measurements from 3 independent experiments {m_1, m_2, m_3}. I have another 3 measurements that are used to scale the m measurements {n_1, n_2, n_3} from the same experiment (different from m)...
34 views

### Example of nonidentification mixture

Consider a continuous r.v. $X$ with pdf $f$ obeying the following finite mixture model for each $x\in \mathbb{R}$: $$f(x)=\sum_{k=1}^K \lambda_k f_k(x) \quad \lambda_k\geq 0, \sum_k\lambda_k=1$$ ...
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22 views

### Statistical test for comparing PCA variation between two groups

I have conducted a Procrustes transformed PCA. I have data from multiple ancient human populations transformed onto the same background of modern reference data. I have a few populations that I am ...
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### In which section of a paper/thesis to report tercile split and dummy coding of variable? [closed]

I'm writing my thesis in psychological research. On one variable I did a tercile split because in other empirical work it is often done so and literature says that most likely there will be effects on ...
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60 views

### What is the connection between lift and logistic regression?

I have noticed that there is an interesting connection between two (apparently different) measures. I am under a market basket analysis framework (aka frequent itemset mining, both are common names) , ...
• 174
11 views

### Are correlated variables in hidden markov model tolerated?

I have two weakly correlated variables (r2=0.66). I want to include these in a hidden markov model (HMM) alongside other uncorrelated variables. I cannot find anything in the assumptions of HMM's ...
1 vote
68 views

### Estimating variance of a Gaussian distribution from the mean of absolute values of first differences in a sequential sample

Edited Question: This question is about estimating the variance (or $\text{SD}_0$) of a parent distribution from which a set of random independent samples is taken. The samples are taken in sequence ...
1 vote
29 views

### Would test set MSE and r^2 be the same with OLS and PC Regression with all PCs? [duplicate]

For this question, I define: PC Regression = Standardize Variables, Fit PCA, then apply OLS to all PCs. OLS = Standardize Variables, then apply OLS with all variables. This question makes me think the ...
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40 views

### Constructing nomogram from approximate model in Regression Modelling Strategies

In section 19.5 in Regression Modelling Strategies by Frank Harrell we make an approximate model using linear regression with ols. Since this is an ols object we have to calculate survival quantities ...
48 views

### Sum of asymptotically independent random variables - Convergence

Let $\theta_N=\frac{1}{N}\sum_{i=1}^N \pi_i\cdot g_i$ where $0<\pi_i<1$ and $g_i>0$ EDITED: such that $\theta_N\overset{N\rightarrow \infty}{\rightarrow}\theta$. If $X_i\sim Ber(\pi_i)$, I ...
32 views

### When to include random-effects in zero-inflation model component?

Is it appropriate to specify random-effects (RE) in zero-inflation (ZI) component of the model? My intuition is that whatever RE is appropriate for main component should be appropriate for ZI ...
31 views

### GLM Reference and Introudction to study my self [duplicate]

I am a third-year statistics student. I have a course in Generalized Linear Models. Unfortunately, the course is taught in French, which is not my primary language, and I am facing some difficulties ...
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17 views

### Firm Fixed Effects Model dropping Sector Dummies? Potential Solution?

For my thesis, I am using panel data with stock returns and other firm data. I first used an event study to calculate abnormal returns (with event window of 7 days so 7 observations for 500 firms) ...
17 views

### How to interpret the results of a classifier when train/test method gives much better results than cross validated one?

I need your help to understand a situation where using train and test set produces perfect results (in terms of accuracy, precision, and recall) but when cross validation is used, the accuracy on ...
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