All Questions

I have a paired data with n=66. I understand that normality condition of differences data should be met to conduct a paired t-test. However, from the histogram, it doesn't appear so normal. The p-...

I'm trying to create my own demogdata and can't get around my error message. My command is ...

I’m currently encountering some problems analyzing a dataset with neural network. The problem is that I have an unbalanced binary class training set (10:1). Training accuracy for both classes are 100%....

We run a business and I am trying to calculate the worth of spending time on our social media groups to book calls with potential clients. I have a list of social media activity for the last 60 days (...

I am performing an engineering analysis to find out the effect of earthquake on concrete buildings. Analysis applies earthquake forces on building model for 50 earthquakes, resulting into separate 50 ...

I am having problems to fit a variogram model, I tried to change some parameters to estimate or fix them but still not archiving any improvement. I remove trend of the data and use logaritm because ...

In python i did cluster. I have a table with 26000 cloth's article and 52 weeks. The values in the table are the sold quantity of every article during the weeks. I'm doing clustering of time series.....

I have a a category variable (Fruit) that I converted to dummy variables: columns Apple, ...

Not a stats major here. The Rand Corporation recently released a study on the US Army's junior enlisted ranks. Here's an excerpt from Table A.1: ...

I am conducting a study on the value of Bitcoin in the period between July 7th 2018 and October 8th 2018. My independent variables are number of discussion and sentiment of discussion about Bitcoin on ...

I am fitting a simple one-dimensional GP model to my observations. My observations are simply the mean number of people/minute who visited a store between different time intervals. So, my data looks ...

Solution Please: Following are the no. of stores in 10 cities: 35, 27, 24, 32, 42, 30, 34, 40, 28, 38. If we want to select a sample of 15 stores, using cities as clusters and selecting within ...

I'm wondering what the best strategy is for collecting the following data. Let's say individuals have signed up to do some kind of task, and they can sign up either by themselves or with a variable ...

There are related questions but the answers don't seem to explain how to practically judge these measurements for non stats users. I have a dataset which I clustered with K=4 using hierarchical ...

I'm analyzing a time series that has this format: ...

My colleague argues to use a Heckman Model in the following case (Agricultural economics): I have a random sample of farmers (n) of the general population N. In n some observations apply a given ...

In neural nets, there is often a weight regularization term in the loss function, which ensures that unnecessarily high weights don't occur. For example, if $C(\theta,x)$ is the baseline loss function,...

Consider the inference '60% events +/- 3%' from a random sample of a binary frame. The complement is '40% non-events +/- 3%. If expressed together (i.e. '60% events AND 40% non-events), would the ...

Asking for a fiend, who has read this. Basically my friend weighs daily and has historical data in CSV format. They would like to take that data and overlay it in some form of weekly chart. E.g shows ...

Let's assume that you have trained your (variational) autoencoder on MNIST digits. After some time, you check the result and decide that the reconstruction is pretty good. But this is highly ...

If just a single unit is drawn at random from the whole population and y1 is the value of y for this sampled unit, how can I prove that the VAR(y1)=by (1 − 1/N)σ^2 (where N is the population size and ...

I have done the following bit myself: ...

I am estimating a survival model with MLE. I use optim to maximize the likelihood function, and I intend to use the Hessian matrix returned by optim to get the standard errors (which lie on the ...

The simple random sampling design considered should more precisely be called simple random sampling without replacement, because it is not possible to select the same population unit more than once. A ...

I have a list of approximately 250 referrers that I need a better ranking system for. I have tried ranking strictly by productivity of referrals however that often results in a ‘one off’ doctor being ...

Is it common that the combination of a regression method and Kriging is performing worse than the regression technique alone? I tested the combination of support-vector machine (non-linear kernel), ...

I am new to ML and as Data Engineer was wondering how the general process of moving ML models to production works. Taking into account fact that many of models are prototyped in notebooks usually with ...

I've got a semester project about statistical methods. One of the questions we have to discuss is the fundametal priniples of the central limit theorem. Is there someone that can help me with ...

I am using the MatchIt package to perform matching between two groups (obese and not obese). The dataset that I am using has no missing data. I am matching on age, sex, and race. Sex and race are ...

For a scientific purpose, I want to analyze the function calls of a software program. The analyzer reports for what reason the function call had been stalled during the execution. For example, the ...

I'm running a economic experiment. From a previous pilot I already know which size of treatment-effect I can expect. Each participant plays 20 rounds, so it't a repeated measures approach. I want to ...

variation measurement with different sample size

Folks, I cannot get the legend to show up for the manually drawn line (on the second line of the below code). Any suggestions on what is wrong? Thanks. ...

I've been reading Schilling's Measures, Integrals, and Martingales, and I ran across a remark (on page 21) that I don't understand. Here is the setup: let $A_{1},\ldots,A_{n}$ be non-empty, ...

Let $y$ be a response variable of size $n\times1$, and $X$ be a covariates matrix of dimension $n\times p$, being $p>n$. Since $p>n$, I cannot directly solve the linear model $\tilde{y}=X\tilde{\...

I am trying to read the Elements of Statistical Learning Tibshirani, Hastie and Friedman, however I have a problem with understanding the expected (squared) prediction error ($EPE$) formula that they ...

I attempt to reproduce elastic net simulation results table on the page 313 of elastic net paper. The authors stated that they simulated 50 datasets consisting of 20/20/200 observations for train/...

comparison of two data set by finding coefficient of variation ?

I am performing cluster analysis (k-means and hierarchical) based on multiple variables. Each variable is in percentage 0-100% and the sum of all variables is at most 100%. I see that in many of the ...

I have a dataset where I suspect the residuals are approximately Laplace-distributed. There are three continuous predictors. When I split up the data into many bins, based on the values of these ...

I am working on a somewhat challenging problem. I have data for a large set of equipment. My main research question is: How many units will fail in each future month in the coming decade? So far I ...

An accuracy $80\%$ of a model that predicts binary outcomes is interpreted as: Given a sample whose outcomes we want to predict, 80% of the prediction will be correct. What does an AUC of $80\%$...

I hope this question can simply be answered conceptually, without a specific dataset. I am planning a new study, for which I will be testing the effects of depression on a memory task. I'm currently ...

Imagine that when we compare treatment A to treatment B (the group A is a high expression and group B is a low expression of gene X) and the pooled hazard ratio (group A in comparison to group B) is 0....

I collected my data (insect biomass) fortnightly from the same trees (six trees) from February to August. The biomass curve looks like Gaussian density curve. I know that I can use optim() to fit the ...

First post, so please be kind... Not sure if the forum is correct, but it was the best fitting on Stack Exchange, so here goes! The following situation is to be examined/evaluated, and I am at a ...

I want to compare two time series and want to find out if there is a significant correlation. Specifically I want to find out if in certain situations there is a specific lag between the series. I ...

I randomly gave to some customers different marketing actions and I observed their response to each action with the amount of money they are willing to spend. So I have two variables. The first is the ...

I have a function: $h(X) = trace(X^TAX)$ $X$ is a matrix with a size of $m$ X $n$. And I am trying to derive $dh/dX$. My attempt: I know that, for function $g(X) = X^TAX$ $\frac{dg}{dX} = (A+A^T)...

I have sentiment data for customer reviews drawn from a larger population of reviews. Each product has a number of customer reviews. Each review has a sentiment (opinion/feeling) between 0 and 1 where ...