# All Questions

139,033 questions
2k views

### Negative BIC in k-means

Probably a simple question but I'm trying to interpret BIC for k-means. I have some k-means clustering and calculating BIC gives me a negative value, with a plot something like this: ...
5 views

### Coefficient Interpretation when dependent and independent variables are percentages

I have built a linear mixed regression model with fund returns (measured in percentage ie. 0.01 denotes one percent) as the dependent variable. For the independent variables I have percentage level of ...
5 views

### How to compute confidence intervals from *weighted* samples?

Imagine we have a webserver, which serves a total of N static URLS. There are users visiting the URLs every day. At the end of each day, we have data like this: ...
4 views

### Mixing average and the Renewal Reward Theorem

I tried to solve the following problem: Buses arrive to an archeological site according to the discrete renewal process with i.i.d inter-arrival times T1, T2, T3, ... which are distributed Geo(p). ...
6 views

### Computing slope of data with correlated errors using Monte Carlo method

I have $N$ pairs of $(x,y)$ measurements. I have the (estimated) uncertainty of each $y$ value as well as the correlations between each pair of $y$ values. I want to know whether there is a ...
2 views

### How to interpret Estimated Marginal Means results

I have used the emmeans() package to calculated the difference between the difference of estimated marginal means. I did this by first calculating the EMMs of location|treatment, and then the ...
95 views
+100

### Why does shrinkage really work, what's so special about 0?

There is already a post on this site talking about the same issue: Why does shrinkage work? But, even though the answers are popular, I don't believe the gist of the question is really addressed. It ...
4k views

### Function with multiple local minima

I am trying to understand gradient descent algorithm by plotting the error vs value of parameters in the function. What would be an example of a simple function of the form y = f(x) with just just one ...
607 views

### Dealing with zeros in a poisson regression

Our code goes through multiple stages of review. I wish to use the number of defects at an earlier stage of review as a "defect density" estimate for later stages. It sometimes happens that code has ...
352 views

3 views

### converting tanh activation output to a probability

I am trying to implement PPO for continuous action spaces so need probability of taking actions from a neural network with a tanh activation in the output layer since the action space ranges from [-2, ...
4 views

### OPTICS Reachability Curve: Scikit-learn VS PyClustering implementations

I am comparing the Reachability curves generated by the OPTICS algorithm using the Scikit-learn (new implementation) VS the PyClustering one. The hyper parameters are not the same, but it seems that ...
11 views

### Difference between “distractors” and “foils”

What is the difference between "distractors" and "foils" in experimental design in psychology?
4 views

### How to calculate accuracy of Mamdani fuzzy inference system?

I have make a Mamdani fuzzy system and know I want to test my 25% test data in that in MatLab, Firstly, I made c4.5 decision tree based on 75% of data then I extract the rules from them, and I import ...
12 views

### Correct C-Vine Configuration to emulate a predefined correlation matrix

I am trying to simulate a vine copula with a predefined dependence structure, so I can generate samples for my desired dependence structure. However, I am having trouble defining the Vine structure ...
6 views

### What is the encoding in VAEs?

The question is actually less broad than it sounds. I generally do understand how variational autoencoders work. From the encoding step we get four parts: mean $\mu$ standard deviation $\sigma$ ...
4 views

### Stochastic gradient variance reduced methods

I'm doing stochastic gradient descent on a non-convex optimization problem. Gradient corresponds to an intractable expectation which I approximate via Monte Carlo averaging. I'm trying to infer the ...
9 views

### Nonlinear Regression with Correlated Error

Assume I have two data sets: Experimentally measured data y for known values $x$. Assume the nature of the error in $y$ is random only and $\sigma_y$ is known/estimated. Simulated (deterministic) ...