0
votes
0answers
5 views

Paired t-test of a non-normal data with sample size 66

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-...
-1
votes
0answers
4 views

Creating personalized demogdata from demography package [on hold]

I'm trying to create my own demogdata and can't get around my error message. My command is ...
0
votes
1answer
4 views

Unbalanced dataset accuracy

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%....
0
votes
0answers
3 views

Which test should I use to determine a relationship between Social media activity and calls booked from activity?

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 (...
0
votes
0answers
4 views

sufficient subsample size for given sample to obtain same regression

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 ...
0
votes
0answers
9 views

Problemes to fit a model for variogram

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 ...
0
votes
0answers
6 views

how i found elements in every cluster in python

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.....
1
vote
0answers
7 views

VIF Drops Significantly When I Delete Some Dummy Variables

I have a a category variable (Fruit) that I converted to dummy variables: columns Apple, ...
0
votes
0answers
11 views

Why does this standard deviation go outside the bounds of the sample?

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: ...
0
votes
0answers
9 views

Bitcoin value time-series. Third-order difference or consider direction of value change?

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 ...
0
votes
0answers
6 views

Adding positivity constraint to GP

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 ...
0
votes
1answer
10 views

Sampling Problem

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 ...
0
votes
0answers
2 views

Designing an individual survey to capture team details

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 ...
0
votes
0answers
3 views

How to interpret contrasting information from the Variation of Information, Dunn and Rand Index for comparing clusterings

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 ...
0
votes
0answers
7 views

Analyze time series (with python) to forecast future and to get trend

I'm analyzing a time series that has this format: ...
1
vote
0answers
6 views

Usage of Heckman estimation for a random sample

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 ...
0
votes
0answers
7 views

“exotic” weight regularization?

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,...
0
votes
0answers
7 views

Are the estimates of a binary proportion and of its complement considered 'simultaneous'?

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 ...
0
votes
0answers
9 views

Searching for a rhythm in weight loss/gain

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 ...
0
votes
0answers
10 views

How to evaluate performance of (variational) autoencoders?

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 ...
0
votes
1answer
27 views

Simple Random sampling with replacement - Variance

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 ...
0
votes
0answers
8 views

How to estimate Breslow type Baseline Hazard for mixture cure model?

I have done the following bit myself: ...
1
vote
0answers
11 views

Inverting Hessian using Generalized Inverse for Inference

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 ...
0
votes
0answers
9 views

Is it possible under this design that any given population unit may be selected more than once? [on hold]

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 ...
0
votes
0answers
5 views

Ranking based on number & production of referrals

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 ...
0
votes
0answers
14 views

Poor Performance of the combination of a regression method and Kriging

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), ...
0
votes
0answers
5 views

Cross framework serialization and desrializatioin of ml models [migrated]

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 ...
0
votes
0answers
10 views

Fundamental principles of the central limit thorem [duplicate]

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 ...
0
votes
0answers
8 views

MatchIt: Explanation of Missing Factors from Summary

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 ...
0
votes
0answers
11 views

Average of some percent numbers [on hold]

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 ...
0
votes
1answer
13 views

Optimal Sample Size/Power Analysis for Panel Data

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 ...
-1
votes
0answers
8 views

coefficient of variation with different (n) [on hold]

variation measurement with different sample size
-2
votes
0answers
8 views

Legend not showing for manually drawn line [on hold]

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. ...
3
votes
1answer
21 views

Atoms of a sigma algebra

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, ...
0
votes
0answers
12 views

How to recover the original coefficients in principal components regression?

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{\...
0
votes
1answer
28 views

Elements of Statistical Learning training set

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 ...
0
votes
0answers
7 views

Elastic net simulation results

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/...
-1
votes
0answers
12 views

can any one help me find the coefficient of variation? [on hold]

comparison of two data set by finding coefficient of variation ?
1
vote
1answer
25 views

In cluster analysis should I scale (standardize) my data if variables are in the same units?

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 ...
1
vote
0answers
15 views

linear model with laplace-distributed residuals, where scale (not location) varies

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 ...
0
votes
0answers
12 views

How can we predict reliability for type 1 censored data?

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 ...
0
votes
0answers
11 views

AUC and accuracy interpretation

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 $80\%$...
0
votes
1answer
12 views

Sample size for 2 groups vs. one large group to measure spread?

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 ...
0
votes
0answers
17 views

hazard ratio interpretation

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....
1
vote
0answers
14 views

Is it possible to fit repeated measure data to Gaussian density curve

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 ...
0
votes
0answers
9 views

Help with a study-design for comparing subjective assessments using different methods

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 ...
0
votes
0answers
15 views

Cross-Correlation of time series with underlying condition

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 ...
0
votes
0answers
17 views

Crossing CDFs, then what to do?

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 ...
1
vote
0answers
19 views

Derivative of a trace of quadratic form [duplicate]

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)...
1
vote
1answer
23 views

Measure spread of non normal distribution?

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 ...

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