2
votes
1answer
45 views

How to find “theoretically best” model?

Given the common problem of predicting response variable $Y$ from predictor variables $X$ and $Z$, is there any way to determine the "theoretical best" prediction possible for a response variable? ...
16
votes
5answers
261 views

Approximate $e$ using Monte Carlo Simulation

I've been looking at Monte Carlo simulation recently, and have been using it to approximate constants such as $\pi$ (circle inside a rectangle, proportionate area). However, I'm unable to think of a ...
0
votes
2answers
23 views

Using a dichotomous categorical variable that has an underlying continuous dichotomy in a multiple regression?

FINAL EDIT I just found a good answer to this question in another thread in the forum here, therefore, I think this question could be closed. Thanks so much for your help and the clarification about ...
2
votes
0answers
30 views

Regression discontinuity design

I am trying to apply an RRD design to a set of spatial data from rasters. The approach has been widely used in the development economics literature and I know that it is a sound methodological ...
0
votes
1answer
33 views

How to combine two measurements of the same quantity with different confidences in order to obtain a single value and confidence

Back in the lab at university, we were taught to measure the quantity of interest some number of times (call this N), and then calculate the standard error. The underlying assumption here is that you ...
2
votes
1answer
34 views

Statistical reasoning in board game [duplicate]

In each round of the board game "The Resistance" three players are randomly and secretly chosen to be spies while the rest of the players are part of the resistance. The spies are then made aware of ...
0
votes
0answers
8 views

Interpretting results in Association - market basket [on hold]

I'm doing a market basket analysis in RapidMiner. The goal is to figure out whether to stop selling a group product "x", there will be drop in sales of other products. The group of product "X" is ...
0
votes
0answers
9 views

References for Combine Seasonal Period in Seasonal Time Series

I'm in a middle writing my thesis. I got confused for find the references which said period of seasonal could be chosen from the small period which already containing another periods. Here is my ...
0
votes
0answers
9 views

which technique will be appropriate for my problem

suppose i have three independent variables x1 x2 x3 and one dependent variable y with following defination x1=test1 scores (20% of final score) x2=test2 scores (10% of final score x2=test3 scores (30% ...
2
votes
0answers
14 views

Proving a property of the Wishart distribution

I would like to prove that, if $X \sim W(V,n)$, then $CXC^T \sim W(CVC^T,n)$ where $W$ is a Wishart distribution. A point in the right direction would be welcome - happy to admit that I may have ...
0
votes
0answers
14 views

Calculate state change probability

I am having telco order management data and need to calculate the probability of each order going through different stages. data is like this: Order No; product_type; time spent in step1; time ...
0
votes
0answers
7 views

Can you give an intuition behind the FTRL update step?

The follow-the-regularized-leader proximal gradient descent uses this update step: $$w_{t+1}= argmin_w( w\cdot \sum_{s=1}^t g_s +\frac{1}{2}\sum_{s=1}^t\sigma_s(w-w_s)^2+\lambda_1|w| )$$ We are on ...
3
votes
2answers
70 views

Time series forecasting with many predictors

Suppose I want to forecast a time series $y$ using its own lags and a large set of potential candidate predictors $X$. The model could be specified as follows: $$y_t = a + \rho \cdot y_{t-1} + \beta ...
0
votes
0answers
19 views

Interpreting factor effect in a logistic regression

Say I'm working with a biological system where two (or more) genotypes are reared under a series of daylength treatments, and scored for a binomial response variable y. I want to know whether the ...
0
votes
0answers
14 views

Estimate number of unique items by number of duplicates in a sample

We have a v. large (1e6) population with unknown number of types of items. We draw a small sample (~100) of a certain size, and find that exactly one item was duplicated. The question is to estimate ...
0
votes
0answers
30 views

I have problem installing packages pbkrtest', 'BradleyTerry2', 'car', 'caret in R version 3.2.2) [on hold]

I have problem installing pbkrtest', 'BradleyTerry2', 'car', 'caret packages. I received the following warning; Installing package into ‘/home/kazem/R/x86_64-pc-linux-gnu-library/3.2’ (as ‘lib’ is ...
0
votes
0answers
14 views

Applying Markov Decision Processes to the Selling House Problem with waiting times

I'd like to apply the Markov Decision Process theory to this problem. We have a house to sell. Each day an offer of $X_n$ comes for the house. Each offer costs an amount $c$ to observe. You may think ...
0
votes
0answers
11 views

Can FTRL be applied on linear least squares? or is it just for logistic regression models?

I'm exploring follow-the-regularized-leader FTRL proximal gradient descent: paper, reference implementation. Everywhere FTRL is mentioned, the loss surface for the gradient decent is the ...
0
votes
0answers
26 views

Error using lrm function with factor [on hold]

When I try to use the lrm function from the rms package I get the following error when I add a factor Error in X[, ...
2
votes
0answers
52 views

Scatter plot with two factor variables for black and white print

How can I best represent a scatter plot with two different factor variables. Consider the example problem, ...
0
votes
0answers
14 views

Averaging and comparing mean values across studies

I am having a statistical problem that falls into two parts: (!) I have several literature reports on studies that have investigated the effect of drug "A" on a particular laboratory parameter. Some ...
3
votes
2answers
53 views

Does cross-validation on simple or multiple linear regression make sense?

Does it make sense to apply train-test split or k-fold cross-validation to a simple linear regression model or multiple linear regression model? I'm really confused about this because I saw this ...
0
votes
0answers
9 views

SMOTE sampling does massively worsens results of Naive Bayes compared to up or down sampling

I train Naive Bayes (NB) and and artificial neural network (ANN) an imbalanced multiclass problem. In order to deal with the imbalance I resample the data set. Using 10-fold cv, the kappa statistics ...
1
vote
0answers
24 views

R: how to plot a cox regression model survival curves (treated vs control curves) using ggplot2? [migrated]

I have a cox model in R that shows time to diabetes. The formula is: ...
1
vote
0answers
11 views

Visualise time dependent transitions/event sequences

Consider the following example dataset consisting of road accidents where both an ambulance and police are called onto scene. There are two possible sequences of events: ...
0
votes
0answers
7 views

fuzzy membership for likert scale

I would like to know how to measure fuzzy membership from likert scale data. Suppose I have 4 parameters, Strongly disagree, disagree, agree and strongly agree. the maximum value is 1 and minimum is ...
1
vote
0answers
13 views

What algorithm or implementation would classify a set of data into one of two groups? [on hold]

My data is in the form of long lists of integers of indeterminate length and where the position/order of the integers in the list doesn't matter, which can be assigned to one of two categories. E.g. ...
0
votes
0answers
6 views

How do I determine true preferences vs random?

Let's say I'm running a dating service. I want to determine if you can decide if you like someone from a profile description. I set up the experiment as follows: A user is presented with 4 ...
-3
votes
0answers
23 views

R. Change som data points (In one column I want to change all the 0's to1) [on hold]

I have a dataset in R. In one column I want to change all the 0's to 1. How do I do that. Some kind of 'if' loop I suppose?
0
votes
0answers
15 views

Forecasting using ARIMA when data available in interval of seconds

I want to use ARIMA for forecasting website visits after some fixed amount of seconds, say 100 seconds. I have csv file available that contain two columns; one is the time and another is the visits, ...
0
votes
3answers
56 views

Why do we do hypothesis testing on estimates of linear regression?

I was reading about linear regression and what I understood is that once we minimize OLS equation we get the beta parameters. Its just like solving a normal equation to get the unknowns. Then why do ...
0
votes
2answers
43 views

What is the mathematical symbol for a predicted value?

Take a simple linear regression $y = ax + b$. Here, $y$ is predicted. In my analysis I need to compare the predicted $y$s to the actual $y$s from my data set upon which the regression was built. What ...
7
votes
1answer
48 views

What are the pros and cons of employing LASSO for causality analysis?

It looks like social sciences are impressed by Statistical Learning and its results. A couple of months ago, I heard Imbens saying: "LASSO is the new OLS". My problem with this is that I've been ...
0
votes
0answers
10 views

R - splitting a vector into three groups, min size, order matters

Hello everyone and thank you in advance for your time. I am looking for the different combinations that could split a vector into three groups (high, medium, low), each group needs to contain at ...
0
votes
0answers
19 views

Measuring change in performance over time

I have two performance scores for multiple companies over a ten year period (10 sets of scores, one set for each year). Which would be the best method to test the hypothesis that one score has dropped ...
1
vote
0answers
19 views

Google Trends: Stitching 90 day periods of daily data together

Google Trends lets you see the amount of researches made on for a term on google during a set period of time, normalized between 0 and 100 (depending on the highest value in that period). I would like ...
0
votes
0answers
24 views

Find Bayes rule/action under given prior

I am able to solve for Bayes actions/rules with no data and am able to follow problems with simple data. However, I'm not sure how to solve a question where the data, $X$, is conditional on the state ...
2
votes
0answers
23 views

Rules of integrated series and balanced regressions

Background There are various rules of linear combinations of integrated series. Let's just consider the $I(0)$ and $I(1)$ cases. For example, if $x_{t} \sim I(1)$, $y_{t} \sim I(0)$, then $ax_{t} + ...
1
vote
0answers
26 views

How to plot a Semantic Differential profile in R? [on hold]

It looks like it's a problem to find R code for plotting a Semantic Differential profile. The only I hardly found: https://github.com/justineuro/sdRplot. Here is the output example, visit . But it ...
0
votes
0answers
21 views

calculating correlation that involves a variable calculated over a certain time period

My research is an education research. I administered a survey at time point 1 (TP1), 2 (TP2), and 3 (TP3). This is a likert-type survey, measures let's say Concept1 and Concept2. The sample size is ...
2
votes
0answers
24 views

PCA to decorrelate and classify timeseries

I have a labeled dataset where each subject belongs to one of two classes A or B, with A ...
2
votes
0answers
31 views

Expectation of a conditional density

I'm trying to figure out why the following equation holds: $$f_{Y}(y) = E(f_{Y|X}(y|X))$$ I have sort of "worked out" the RHS to be: \begin{align} f_{Y}(y) &= E(f_{Y|X}(y|X)) \\[5pt] ...
0
votes
0answers
16 views

Two-stage sampling with R [on hold]

I have been trying to do a two-stage survey sampling using the mstage function. My sampling frame consists of 23 primary sampling units (...
0
votes
1answer
34 views

Having trouble making a scatterplot out of my data in R studio. [on hold]

As the title says. Instead of a typical scatterplot with an x and y axis, I get something with a third increment on the right side of the graph. What am I doing wrong?
0
votes
0answers
9 views

If you transform response time data, e.g. to generate a CI, do you transform the values back for interpretation? [duplicate]

I would like to create a CI or highest density interval for response time data. The distribution of the response times is quite skewed and I think about transforming them by LN(y). However, my ...
0
votes
0answers
5 views

Node dimension does not match in WinBUGS [on hold]

I'm using WinBUGS14, though I am not adept at it. I have worked through several problems before, however, this error seems to be tripping me up. Node dimension does not match This EXACT code has ...
0
votes
0answers
45 views
1
vote
0answers
12 views

Conceptual help with scalar invariance testing

I'm having trouble understanding why scalar invariance is needed in testing a certain type of model. Let's say I have employee and supervisor ratings of deviance. I want to look at what happens when ...
1
vote
1answer
23 views

Metaanalysis - how big should be the ICC (Intracluster correlation coefficient)?

The background is a metaanalysis of cluster randomised clinical studies. The included studies report no ICC for final values, the chosen ICC for the calculations was 0,02. Similar studies in the same ...
0
votes
0answers
15 views

Performing PCA on a tetrachoric matrix in SPSS

I am currently working on a project where I have nine dependent variables, each binary, measuring similar outcomes. Accordingly, I'd like to perform a principal component analysis on them to reduce ...

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