0
votes
0answers
3 views

spss principal axis factoring output problem

I am trying to run a factor analysis (SPSS) using principal axis factoring with an oblique (or promax) rotation because the variables are highly correlated. However, the output for "total variance ...
0
votes
1answer
4 views

Question regarding parameters and variable selection in Mahout algorithm for logistic regression

Below is the list of parameters in Mahout logistic regression. What does "passes" mean? In detail please --passes passes the number of times to pass over the input data ...
0
votes
0answers
2 views

Calculating distances between centroids in an Primer 6 MDS plot

I am just wondering if there is a way to calculate the distances between the centroids generated by Primer 6 in a MDS plot. I am trying to find if the centroid distances change beween samples but I ...
0
votes
0answers
8 views

Experiment design

We have x1 and x2 representing variations in temperature and pressure and the response is yield of penicillin. What is the practical reason for using the points (-1,-1), (-1,1), (1,-1), (1,1) rather ...
2
votes
2answers
12 views

simulate dirichlet process in R

I am reading the paper of Dirichlet Process Mixtures of Generalized Linear Models authored by L. A. Hannah. If I would like to simulate the following model In R, ...
0
votes
0answers
3 views

Decision Level Fusion of SVR outputs

I have two sets of features predicting the same outputs. But instead of training everything at once, I would like to train them separately and fuse the decisions. In SVM classification, we can take ...
2
votes
0answers
9 views

Residual plot for regression tree: What should it look like?

I realize that decision trees are nonparametric methods What should residual vs. actual/fitted look like for a well behaved regression tree? My argument would be that since each observation assigned ...
0
votes
0answers
13 views

Hypothesis test on a series of wagers with different probabilities and returns

I have a model that predicts the probability of an event occurring, and then based on a given return if the event occurs, calculates the expected value. If the expected value is positive, a wager is ...
0
votes
0answers
8 views

statistical comparison of power spectrums over all frequencies

So I have N=147 control time-series signals and N=134 treatment (THC) signals. I want to compare if there are any significant differences in frequency power in the two groups. The top part of the ...
0
votes
1answer
22 views

Why does eigenvalue decomposition of a correlation matrix maximizes possible variance?

I was reading up on principal component analysis and I was wondering how does eigenvalue decomposition of the correlation matrix maxmimizes the possible variance that is captured? Can someone refer to ...
0
votes
0answers
10 views

Possible problem for Network Analysis

I have a data set and I want to examine an hypothesis in there and probably Network Analysis should prove or reject my theory. I have a list of products and a group of people who give the product to ...
0
votes
0answers
6 views

Deep belief nets and PCA

I have been using successfully DBNs for classification for MNIST and some other tasks. I was thinking of doing dimensionality reduction before training, in order to boost performance. However, when I ...
1
vote
0answers
16 views

Is my dataset suitable for a mixed effects model?

I've been putting a lot of work over the last few days into bring mixed effects models to bear on some behavioural data I've collected for my thesis, but it's occurred to me that I'm not 100% sure ...
1
vote
2answers
41 views

Increasing power of test by transforming format of data - is this cheating?

I'm working on a health care dataset that contains one row per member, measuring total number of the member's hospital inpatient (IP) visits during 2012 and 2013. The initial research question of the ...
1
vote
1answer
9 views

Tolerance for pseudoinverse

In calculating the pseudoinverse of a matrix $A$, of size (m,n), I need to choose a tolerance threshold for the eigenvalues. I'm trying to understand how I should pick this. Matlab default is to use ...
0
votes
0answers
7 views

R latent class multinomial logit model

I am using the flexmix package to estimate latent class multinomial logit models in R. In choice theory, there can be variables associated with the alternative ...
0
votes
0answers
11 views

R: result of Levene test correct?

I want to use the Levene test to quantify the homo/heterogeneity of the variances of two samples. The density plot looks like this: But the Levene test for the data [...
0
votes
0answers
26 views

$\text{cov}$$(\hat{y_i}, \hat{y_i}^*)$ follow-up

Consider the model: $ {y_i}= {\beta_0} + {\beta_1}x_i + \epsilon_i$, where $E[\epsilon_i]=0$ and $var[\epsilon_i] = \sigma^2$ for $i = 1, 2, ..., n.$ Let $\hat{\beta_0}$ and $\hat{\beta_1}$ be the ...
2
votes
0answers
25 views

Is there a measure of covariance for larger dimensions?

Can you measure the covariance of three or more variables simultanesously?
1
vote
1answer
30 views

Power calculation of study using 2 sample z-test

This is not homework! I have two very different answers for a power calculation I have done on the below data - ...
0
votes
0answers
10 views

How do I create a transition matrix in Stata (and export it to excel)? [migrated]

I have data that looks something like this (in Stata): ...
1
vote
0answers
11 views

Visualizing Mutual Information Against TF-IDF for Text Corpus Data

I'm working on a data visualization project for the semester and have decided to work with a corpus of discussion forum data focused around debate over political issues (available here). I'm ...
0
votes
0answers
8 views

arima function in R, data= and subset= not available? How to specify training set?

I would like to fit my arima model on some subset of my full data, say, based on observations within a certain time range. Normally, say in fitting an lm() object, I would use the subset= argument ...
0
votes
0answers
10 views

How to measure pre- and post- intervention effect with single metric capturing percent and absolute magnitude of change?

My colleagues and I are attempting to best quantify the benefits of an intervention program on the number of emergency department (ED) visits per patient during pre-intervention and post-intervention ...
5
votes
1answer
27 views

Multiple regression in directional / circular statistics?

I'm trying to develop a predictive model for an angular dependent variable (on $[0,2\pi])$ using several independent measurements – also angular variables, on $[0,2\pi]$ – as predictors. Each ...
1
vote
0answers
8 views

Is there an R function to do a survival analysis with right censoring + nested + crossed factors

I have this dataset to model, but I'm not sure how to do it. I want to model the surviving probability of different populations of two species depending on a treatment applied. Populations should ...
3
votes
1answer
19 views

Imputation before or after splitting into train and test?

I have a data set with N ~ 5000 and about 1/2 missing on at least one important variable. The main analytic method will be Cox proportional hazards. I plan to use multiple imputation. I will also be ...
0
votes
1answer
11 views

PLS Regression and collinearity

From what i know PLS regression is used when there is more variables than observations and when there exist multicollinearity between the independent variables. I have data for a regression model that ...
0
votes
0answers
13 views

Finding optimal parameter values using a Bayesian model

I have a problem with the following setup. I've been reading "Doing Bayesian Data Analysis: A Tutorial with R and BUGS" and it seems like the Bayesian approach is a good one, but I'm not entirely ...
0
votes
0answers
19 views

Specification of a mixed model with nesting with lmer

I've been told my model wasn't statistically correct, but I'm not sure what I should do. What I have is basically 2 species: A and B. For each species, I have 3 replicates: 1, 2, and 3 (=6 ...
1
vote
1answer
32 views

Scatter plot in R with non numeric data

I need to represent some non numeric data of a questionnaire in a scatter plot in R. What I mean by a non numeric data is that, I have two questions answers to which are some text. For example Q1 has ...
1
vote
2answers
39 views

How important is it to include a hypothesis for a report?

I am writing a research report for my final university project. For my analysis I have used logistic regression. I have provided research questions which have been answered. So, how important would ...
2
votes
1answer
25 views

Distribution of MLE of $N$ based on a random sample of size n from discrete uniform dist.(1,2,…,$N$)

Let $X_1, X_2, ..., X_n$ be a random sample from discrete uniform distribution on $(1,2,\ldots,N)$, where $N$ is an unknown positive integer. Find MLE of $N$ and also find the distribution of the MLE. ...
0
votes
1answer
15 views

How is the prediction variance defined?

I wonder how the output $var.pred returned by ar.ols() in R is defined? It is not the variance of a prediction value, is it? I ...
0
votes
0answers
7 views

F statistic (degrees of freedom) with lagged regressors

Hopefully a very simple question: If we're told we have n observations, but the model we're evaluating is $$ y_t = \alpha + \sum_{i=0}^{p}{\beta_i x_{t-i}} + \epsilon_t $$ And say I'm testing $ ...
0
votes
0answers
4 views

comparing bootstrapped specific indirect effect sizes SEM

When looking for specific indirect effect sizes (lets say we have several series of mediators between "A" and "B"), I have runned nested models. In one model (lets call it, "happy face") I constrained ...
0
votes
1answer
18 views

Is there any way to merge two conditional probability distributions?

Is there any way to construct an expected conditional probability distribution of the form p(x|(y,z)) if I am starting with p(x|y) and p(x|z)? All variables are categorical. My specific problem deals ...
0
votes
0answers
18 views

Piecewise nonlinear regression by MLE in R software

I have been working with nonlinear models whose parameters have been estimated by Maximum Likelihood. Also, I use the "Vuong" test for model selection in non-nested models, this test requires to have ...
1
vote
0answers
6 views

What do I do with zero columns in a tensor.prod.model.matrix?

Suppose my two marginal bases are given by (for variable $p$ and $t$ the degree is equal to $1$ and $5$ inner knots are used). ...
0
votes
0answers
8 views

Efficient evaluation of multidimensional kernel density estimate

I've seen a reasonable amount of literature about how to choose kernels and bandwidths when computing a kernel density estimate, but I am currently interested in how to improve the time it takes to ...
0
votes
0answers
12 views

How to get the overall effect for linear mixed model in lme4 in r?

I would like to get the significant value and effect size of the independent variable in overall, rather than the normal output from lme4 in R. It is just like the thing people report when running ...
2
votes
0answers
57 views

Is Big Data the end of Statistics? [on hold]

Statistics emerged as a discipline whose goal was to allow inferences about inaccessible populations from data obtained from its samples. Does modern access to huge amounts of data depreciate the ...
2
votes
0answers
26 views
0
votes
1answer
22 views

Which type neural networks for time series classification

I would like to use neural networks to classification of time series ( I have some Patterns and I want to adjust input time series to an appropriate class) -ist it possible to do this job with ...
0
votes
0answers
5 views

Lagrange-Multiplier test for Serial Correlation

When testing whether $\epsilon_t$ is serially correlated in: $$y_t = \alpha + \beta_1x_{1t} + \ . . . \ + \beta_kx_{kt} + \epsilon_t $$ Can we simply test: $H_0: p = 0$ in the following: $$y_t = ...
0
votes
0answers
13 views

What kind of test should I do and how many participants do I need for this?

I am designing new functionality in a web application, and I am testing two variations on the navigation to attempt to determine which approach is more successful for our users. I am running the test ...
4
votes
1answer
38 views

How does Factor analysis explain the covariance and PCA explains the variance?

As I read in Bishop's PRML (here is the clip of that part about FA): According to the highlighted part, factor analysis captures the covariance between variables in the matrix $W$. I wonder HOW? ...
0
votes
0answers
7 views

Linear correlation in ANCOVA - necessary?

I've been told by my stats prof that running an ANCOVA relies on a series of assumptions, including that the the dependent variable and the covariate are linearly related. So, in SPSS the first thing ...
0
votes
2answers
14 views

analysing difference in variability between multiple related time series

I have constant time series (yearly from 1950 to 2010) of the abundance of several species that were captured by different groups. These series are somewhat related because the quantity of all species ...
0
votes
0answers
4 views

When is Micro-average Precision = Micro-average Recall

This page describes briefly on micro and macro precision used in computational evaluation: http://rushdishams.blogspot.de/2011/08/micro-and-macro-average-of-precision.html This paper surveys the ...

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