0
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
0
votes
0answers
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: ...
1
vote
2answers
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 ...
1
vote
0answers
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 ...
1
vote
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
-1
votes
0answers
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.
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
9 views

Finding ACVF and two random variables

let $X_t = 0.5X_{t-1} + Z_t$ where $Z_t$ ~ $ WN(0,\sigma^2)$ I want to find the ACVF of both $X_t$ and $Z_t$, but I am a little bit confused. Say for $X_t$ $$\gamma(h) = Cov(0.5X_{t-1} + Z_t, ...
1
vote
1answer
26 views

calculating percentiles for transformation into standard normal quantiles

I'm trying to hand calculate a standard normal quantile plot. The first step involves transforming the data into percentiles. That sounded like the easy part, but apparently there are several ...
0
votes
0answers
14 views

Regarding Naive Bayes and conditional independence

We all have been talking about how Naive Bayes may, in some cases, not perform well due to the fact that this assumes conditional independence of features and MOSTLY, this is not true for real world ...
-1
votes
0answers
15 views

Probability of occurance of events in time-window [on hold]

Question: After locking the car, what is the probability that car may be unlocked within X seconds? If X is 1 seconds, then I guess probability is very low. If X is say 60 seconds, then probability ...
6
votes
1answer
377 views

Why should we use t errors instead of normal errors?

In this blog post by Andrew Gelman, there is the following passage: The Bayesian models of 50 years ago seem hopelessly simple (except, of course, for simple problems), and I expect the Bayesian ...
0
votes
0answers
10 views

how many questions per construct to include on survey

I am developing a survey that tests a number of different constructs relevant to a particular educational intervention and subsequent educational outcomes. For most of the constructs, the questions ...
0
votes
0answers
18 views

Selecting the right BIC value

I'm using the hddc for an assignment to find the optimal number of clusters. The dataset is 9-dimensional and consists of 200.000 rows, however, the BIC values that I'm getting are really high. How ...
0
votes
0answers
5 views

Dealing with singleton strata in survey analysis

I am primarily using Stata for my survey analysis, but my question is also applicable to R or SUDAAN. There are a number of different ways of accounting for singleton strata in survey analysis. Just ...
0
votes
0answers
22 views

mixed effect regression model

I would like to expand over a previous question of mine (What is the correct model for this experiment design?), with slight modifications... To set up the scene : We have a completely randomized ...
0
votes
1answer
26 views

R lme4 1.1-7 glmer: p values for fixed effects in summary() and likelihood ratio test comparison

I'm using glmer() with a binomial response variable. My optimal model has two fixed effects (flow and DNA) which in summary() show a non-significant p value but ...
0
votes
0answers
17 views

Generate observations from an autoregressive process [on hold]

I'm wondering how I could go about generating data from an AR process, for example: $$y_t=0.2+0.5y_{t-1} +e_t$$ where $e_t\sim N(0,1)$ with $y_1=0.2$ I need to generate 100 observations from ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
1
vote
1answer
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. ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
1
vote
1answer
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 ...
0
votes
1answer
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?
1
vote
1answer
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 ...
0
votes
0answers
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: ...
0
votes
0answers
57 views

Small loadings in all variables, PCA analysis is ok?

I'm performing a PCA analysis on a set of 5 variables, whose correlation matrix is: ...
0
votes
0answers
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 ...
0
votes
1answer
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 ...
0
votes
0answers
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: ...
0
votes
0answers
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 ...
5
votes
2answers
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, ...
0
votes
0answers
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(). ...
0
votes
0answers
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 ...
-1
votes
0answers
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 ...
1
vote
1answer
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 ...
1
vote
1answer
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: ...
0
votes
1answer
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 ...
0
votes
0answers
15 views

time-series forecasting - predicting av. error intervals

I should start with the disclaimer I'm not proficient with R or heavier statistical terminology, sadly! Nevertheless I create sales forecasts (using different methods such as holt-winters), and I'm ...
1
vote
1answer
84 views

Mutual Exclusivity

Suppose that a study is being done on all families with one, two, or three children. Let the outcomes of the study be the genders of the children in descending order of their age. A. List sample ...

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