# All Questions

16 views

### Show about an arbitrary measurable function that has density

This is an exercise that I have to finish and I hope you to be patient maybe I violated the rules since that it is not always possible to start solution of an exercise. Maybe can be very useful only ...
29 views

### “Frequency” value for seconds/minutes intervals data in R

I'm using R(3.1.1), and ARIMA models for forecasting. I would like to know what should be the "frequency" parameter, which is assigned in the ts() function, if im ...
20 views

### Convergence of Monte Carlo sample average for arrays of random variables

Suppose $X_1$, $X_2$ are two independent real-valued random variables. Let $F$ be a continuous (unbounded) function from $\mathbb{R^2}$ to $\mathbb{R}$. Assume that the necessary measurability and ...
3 views

### extract data.frame() from group_by() [migrated]

I'd like extract a data.frame produce by group_by() function of the dplyr package on R. My original data looks like this: ...
36 views

### Ordinal logistic regression with non-negative independent variables

If I understand things correctly, we want to look at $log(p/(1-p))$ since we want the independent variables to be able to take on any real value. But what if you know your independents can never be ...
50 views

### GLMER: Conflicting results from p values and bootstrapped confidence intervals

Please don’t be shocked by the amount of code in this post, this problem is (hopefully) not as complex as it seems. This dataset ...
21 views

### Analysis of a longitudinal study where interventions are received at different time points

I have a data set of university students. The university has 8 different assisting programs, mostly like scholarships, for needy students to help them concentrate on their studies. Since it costs a ...
15 views

### Examining the Win Probability of a Particular Play-style in a Set of Tournaments

Something I've been playing around with in my head, which I'd like some advice on. Assume you have a game with four different "play-styles" - this can be a particular strategy, different team ...
13 views

### Model Averaging

Good Afternoon, I am working on model averaging of data collected about bird species and habitat vegetation. I have been using the MuMIn package in R and have taken a subset of all possible models ...
11 views

### markov proof for poisson process and question 2 [on hold]

I want answers for those 3 questions as soon as possible.I can't understad those stuffs.
16 views

### SAS Enterprise Guide - are there any alternatives? [on hold]

What software is the closest alternative to SAS Enterprise Guide? I am interested more in visual representation of complex data queries (more ETL-like) and not as much in statistical ...
9 views

### multinomial logistic regression with transition period

given data that has to periods t0 and t1 and in each period there are two categories that a subject can be in {a,b} would there be an inference problem to formulate a multinomial logistic model as ...
9 views

27 views

### Multivariate regression with categorical response variables

Explanation of Data: I started with a data set where each user belong a specific group and their contribution to different domains. After multiple pivots and pre-processing attempts, I got my data in ...
12 views

### Binsize for Compound Poisson Gamma Distribution

Having data of a (putative) Poisson-Gamma process I am looking for a method to define the correct binsize for analysing my data. I need a certain range (!) of binsizes (for instance starting with ...
19 views

### Open source web-widget to visualize graph data? [on hold]

I want to use a web-based applet to visualize the results of a data analysis. My result data are graph structures (nodes, edges, edge weights, labels, and all that jazz). Other than tools like gnuplot ...
15 views

### Getting estimates of hospital specific stroke admissions data

I am analysing a small data set on stroke process of care gathered from public sources but don't have access to hospital specific emergency stroke admissions over a period of time data except for ...
70 views

### Not sure about the interpretation of this residual plot

I'm analyzing a residual plot of the residuals vs the fitted values. I'm not quite sure how to interpret this plot since there looks like there is a pattern and the average is not actually zero. ...
19 views

### How to enter data into contingency table directly?

I'd like to create a contingency table. I do it using: matr=matrix(c(62,61,36,19,10,21,58,60,39,22,12,19,91,83,72,23,52,62,43,28,59,57,29,20,12),5,5) but it ...
21 views

### Correlation between a variable and a function of independent variables, and their significance

Consider a variable $Z$ which correlates at a significant level with $Y$. We know that $Y(X_i)$ and that several $X_i$ correlate with $Z$, but at a non-significant level. Doesn't the correlation ...
16 views

### Heavy-tailed RBF kernel function

I'm trying to run a SVM regression on some data and I want to use ksvm from kernlab or svm ...
22 views

### Phylogenetic General Least Squares, Multivariate Regression

I'm working on a biological question, with species data derived from an external database, which has multiple response and predictor variables. As a result, I want to do multivariate regression across ...
28 views

### Cointegration with dummy variables?

Let's say I'm interested in the relationship between poverty (measured by some continuous variable) and different types of financial reforms (which are dummies). Given this does it make sense to ...
37 views

### Selection of regressors into a regression model

Why is it that backward selection/elimination as compared to forward selection of regressors, is often less adversely affected by the correlative structure of regressors?
17 views

### How to construct appropriately reverting geometric AR(1) process?

Suppose I have a mean-reverting AR(1) type process, $X_{t+1} = X_t + \theta(\mu - X_t) + \epsilon_t$ where $\theta > 0$ and $\mathrm{Var}(\epsilon_t) = \sigma^2$. This process is clearly ...
29 views

### Determine the causes of change in time with mixed models

I have a database with several continuous variables measured in two times. I searched for a change in time in my dependent variables in this way: ...
57 views

I'm performing a PCA analysis on a set of 5 variables, whose correlation matrix is: ...
4 views

### given a set of pairs of graphs, build a model that accept a graph and predicts it matching graph

Training Data I have a set of pairs of normally distributed graphs, each with a concrete last sample (maximal X) Question I want to build a model (formula) from the data input: a single graph ...
22 views

### Question in Artificial neural network normalization

I wish to normalize inputs parameters into [0 - 1] and fit into a neural network for training. I have done a simple normalization method - MinMax Question 1: if my inputs have negative values, do i ...
22 views

### How to interpret ANOVA output comparing two models

I'm working with the Blackmoor data from the study "Female adolescents with anorexia nervosa and their parents." I've made 4 models based on this: ...
16 views

### Is scaling data valid for Kruskal-Wallis test?

I have a dataset of fresh matter (FM) weights of salad measured in field over time (6 Dates, 40 Plants each). Those are measured independently, so at every date different plants were measured. As in ...
201 views

### Does adjusting for superfluous variables bias OLS estimates?

The usual textbook treatment of adjusting for superfluous variables in OLS states that the estimator is still unbiased, but may have larger variance (see, for example, Greene, Econometric Analysis, ...
35 views

### Using principal components to perform further PCA

I am working with principal component analysis for the first time. I have managed to extract the principal components of one set of data (say data1) using prcomp(). ...
5 views

### What are the Outputs of analytic process

I am trying to understand the different types of output generated as a result of the analytic process. If my customer does not understand Linear regression, Random Forest, then what is the best way of ...
15 views

### Data mining tool for mining e-mail data?

I am very new to Data Mining and need to perform it in on the e-mail data set of an organization in order to extract information from the subject and the body of the message. Note that the objective ...
43 views

### Choosing predictor for regression

If a predictor is almost the same as the criterion (different tests measuring same domain and they are both highly correlated) would that predictor be worth-including in the regression model? What if ...
22 views

### Best parameter to compare treatment and control groups?

In a study, drug was given to tt (treatment) group and not to cc (control) group and blood levels of (say) cholesterol were tested before and after in each subject. I have following data: ...
18 views

### pairwise comparison with Dunnett's adjustment in Stata

I am comparing the means of days between notification and diagnosis for 13 years, as I want to know if the mean days from 2013 is significantly different from the previous 12 years. I was thinking ...