All Questions

0
votes
0answers
4 views

Find The Best Two Predictor Variables Used Conjointly, And Levels Of Each

Twenty possible predictor variables in data set. One outcome variable. The predictor variables are not linear. So a straight linear multivariate regression probably won't do. Example: Time of ...
0
votes
0answers
38 views

Need someone's endorsement to publish a pre-print on arXiv [closed]

I wish to put up my manuscript on arXiv, in the stat.ME (statistics-Methodology) section. Since this is the first time I am putting up a manuscript in the statistics section, the arXiv is asking for ...
2
votes
0answers
20 views

Examining correlation and long range dependence in time series data with strong diurnal effects

I have data sets of network traffic that exhibit strong diurnal effects making them non-stationary. One of the analysis that I want to run is to show correlation between days. If we chopped up the ...
1
vote
1answer
30 views

What is the probability that a multivariate Normal RV lies within a sphere of radius R?

I am currently using different procedures to estimate the probability that a $D$-dimensional Gaussian random variable with mean $\mu$ and covariance $\Sigma$ lies within a sphere of radius $R$ that is ...
1
vote
1answer
15 views

Clustering using the BIRCH algorithm

I am trying to solve this question: Build a CF-tree for the subset of points, (3,3) (4,3) (6,3) (7,4) (7,5) assuming that the branching factor, B, is set to 2, the maximum number of sub-clusters at ...
3
votes
0answers
25 views

Linear mixed-effects modeling with twin study data

Suppose I have some some response variable $y_{ij}$ that was measured from $j$th sibling in $i$th family. In addition, some behavioral data $x_{ij}$ were collected at the same time from each subject. ...
0
votes
1answer
24 views

Normality in repeated measures ANOVA

I'm a little confused about the analysis of normality in a repeated measures ANOVA I'm doing. It's a factorial ANOVA with three rm IVs each of which has only 2 levels. I've read in a few places online ...
1
vote
1answer
23 views

How do I test whether I can properly apply LDA?

I have some data which works nicely with JMP's canned linear discriminant analysis (LDA), but after reading about LDA I'm not sure if the analysis is valid. The Wiki article notes a fundamental ...
0
votes
1answer
29 views

Dirichlet process/Chinese restaurant process for clustering in R

I recently read a fascinating article describing methods for clustering data without assuming a fixed number of clusters. The article even includes some sample code, in a mix of Ruby, Python, and R. ...
4
votes
2answers
51 views

Classes of distributions closed under maximum

Let $Q_p$ be a class of probability distributions on non-negative reals parametrized by $p$, so that $$ Q_p([0,\infty)) = 1. $$ I wonder which known classes of distributions are closed under ...
1
vote
1answer
30 views

Constructing a Bayesian network from the begining

I am trying to construct a bayesian network which detects fraud.I have got a huge data set, with elements such as country, top spend merchant just to name a couple. The first part of my problem is to ...
0
votes
0answers
20 views

JAGS: unobserved parents and intialization

I have a very simple multinomial logistic regression problem; it's a simplified version of the alligator lake/food/size BUGS example. In my case I have (effectively) lake/food and have just stripped ...
2
votes
2answers
51 views

Wondering what this bean plot analysis chart means

How does one interpret and generate bean plot charts. Here is one example taken from Walkes et al. 2010. What kind of data is it most useful for?
1
vote
0answers
15 views

regularized bayesian logistic regression in JAGS

There are several math-heavy papers that describe the Bayesian Lasso, but I want tested, correct JAGS code that I can use. Could someone post sample BUGS / JAGS code that implements regularized ...
0
votes
0answers
14 views

Real utility of small accuracy improvements in sentiment classifiers

I have lately been reading papers regarding Sentiment Analysis, where most researches report that their improvements made them achieve an increase of 1~2%, or even 0.5% in accuracy compared to ...
1
vote
1answer
29 views

Joint confidence intervals for probabilities

I have two probabilities $p$ and $q$. $p>q$, and they aren't correlated. I'm going to calculate $i$ such that $p^i=q$, which is easily done as $\log_p(q)$. Now, I'd like to also calculate a ...
0
votes
0answers
17 views

Multilevel mixed model in SPSS

We are running a study in which we have 42 participants, who each complete 72 trials. Within each trial, skin conductance is measured every 100ms. This gives a repeated measures multilevel structure, ...
-2
votes
1answer
30 views

Optim error - initial value in vmmin is not finite [closed]

I have run 'fitdistr(mydata, "Gaussian")' and get the following error message: Error in optim(x = c(34.513, 25.587, 18.251, 52.836, 38.206, 42.395, 47.22, : initial value in 'vmmin' is not ...
1
vote
1answer
28 views

How to run two-way ANOVA on data with neither normality nor equality of variance in R?

I am working on my master thesis at the moment and planned on running the statistics with SigmaPlot. However, after spending some time with my data I came to the conclusion that SigmaPlot might not be ...
0
votes
1answer
27 views

Maximizing: likelihood vs likelihood ratio

Say I have an observed data set ($n_i$) and I want to obtain the best fit out of 10 data sets produced by a model dependent on a single parameter $a$ ($m_i(a)\;a=1..10$). Suppose I use a Poisson ...
0
votes
1answer
27 views

how to group time series data into stationary & non-stationary?

i have time series data (download at:-->http://www.4shared.com/rar/ft3YCN2H/Time_series_data.html) consider potential values as time series data points(4th column) ...
1
vote
0answers
10 views

Specify variance structure in ASreml v3

i used ASreml to estimate genetic parameters for feed intake. Using bivariate and multivariate models. However, i am confusing very much about how to defining variance structures (even i went through ...
0
votes
0answers
18 views

Interpretation of non parametric regression with control variables

There seems to be a lot of examples in the literature of empirical non-parametric studies that estimate models with one dependent variable and one independent regressor. However, the literature ...
3
votes
0answers
46 views

Mahalanobis distance distribution of multivariate normally distributed points

I'm trying to understand the properties of Mahalanobis distance of multivariate random points (my final goal is to use Mahalanobis distance for outlier detection). My calculations are in python. I ...
0
votes
1answer
16 views

Calculate trend slope after STL decomposition

I have a time-series of daily measurements of some quantity for 1995-2011. There's about one measurement every three days. The data show a strong seasonality (annual cycle). What I ultimately want ...
0
votes
1answer
14 views

Outlier and structural break detection in dynamic linear models

Is there a non bayesian method of finding outliers and structural breaks using the pakcage 'dlm'?
1
vote
2answers
78 views

Detecting fishy data

Just a little thought I've been having. If we rolled a fair dice 60 times, and got 60 sixes in a row, we would (wrongly?) definitely assume that something fishy's going on. Is there any statistical ...
0
votes
1answer
37 views

Whether to use nonparametric tests to compare two groups when sample size is large but assumptions are violated

I have a data set that has 600 observations divided in two groups. I am going to compare the central tendencies (e.g., the means) of these two groups. However, there are violations of classical ...
0
votes
3answers
93 views

Filling NAs in a dataset with column medians in R

I have a massive dataset with titles across the top for the row. All the values in the dataset are number minus about 50 of them which are NA. I need to find the median of each column whilst somehow ...
2
votes
1answer
14 views

Proper order of variables in unbalanced ANOVA

If you have unequal sample sizes in cells, then the order in which you enter model terms changes your results for sequential or Type I SS. The first variable to enter the model is allocated its ...
0
votes
0answers
37 views

Blocking and confounding in replicated $2^k$ factorial design

Consider the $2^6$ factorial in 8 blocks of eight each runs with ABCD, ACE and ABEF as the independent effects chosen to be confounded with blocks. Generate a design. Find the other effect of ...
2
votes
1answer
28 views

What is correct terminology when describing the number of response levels of a Likert scale?

I know that the Likert scale is the sum (or some sort of combination) of all the responses of a survey, test etc. and the actual numeric responses are called response levels. Is this true of all ...
0
votes
0answers
10 views

What's a good range of weights to evaluate for L2 regularized logistic regression?

I want find a weight that minimizes an averaged cross validated misclassification score from a L2 logistic regression classifier. Obviously, the search space for the weights should be bounded below by ...
2
votes
2answers
26 views

Does having self an other report measures as predictors require dyad analysis?

I have three different measures of child anxiety (IVs). For each measure, I have a self-rating by the child and an other-rating by a parent. I want to use these measures to predict a particular ...
0
votes
0answers
22 views

Distribution of block occurrence of random vector in $\mathbb{Z}_2^n$ [migrated]

Given natural numbers $m, n \geq 2$ and a random vector $\mathbf{r}= (a_1,a_2,\cdots,a_n)\in\mathbb{Z}_2^n$. We define the $m$-circulant of $\mathbf{r}$ by the vector ...
5
votes
2answers
93 views

Is there a general method for simulating data from a formula or analysis available in R?

In designing an experiment or a survey, simulating data and conducting an analysis on this simulated data can provide terrific insight into advantages and weaknesses of the design. Such an approach ...
1
vote
1answer
35 views

Is there a fuzzy distinction between discrete and categorical variables?

Are there some variables where it can be difficult to assess whether they are purely categorical? For example: To assess the level of pain that a patient is in, you use a scale between 1 and 10.I ...
0
votes
1answer
30 views

Best distribution to model durations

I am struggling to find an appropriate distribution to model the total number of vacation days taken in a year. I originally thought of going with a standard count distribution like negative binomial ...
2
votes
1answer
86 views

What do additional arguments indicate in the simple.sim function in R?

In R suppose that we have the following code: require("UsingR") # required for "simple.sim" function below f= function(n=100,mu=0,sigma=1) { nos = rnorm(n,mu,sigma) ...
0
votes
1answer
28 views

Cox model with missing covariates

I was wondering if any of you have experience fittng a Cox model to data with missing covariates. Do you know of any reference addressing the issues associated of missing covaraites in Cox ...
-1
votes
0answers
45 views

Ridge regression auto-normalization & CV

Is there a package in R that performs regularized regression (ridge, Lasso, LARS, etc.) that also: unit normalizes (i.e. scales and de-means) independent variables automatically AND uses ...
3
votes
0answers
75 views

Regularization L1-norm and L2-norm empirical study

There are many methods to perform regularization -- L0, L1, and L2-norm based regularization for example. According to Friedman Hastie & Tibsharani, the best regularizer depends on the problem: ...
0
votes
0answers
21 views

Multi Class vs 2 class Naive Bayes

I was wondering what are the implications of using a multi-class Naive Bayes versus a 2 class Naive Bayes (for one against everything). Which technique performs better? I've previously came across ...
1
vote
0answers
76 views

Variance preserving, order reversing transformation

Given a dataset $X$ with $k$ "time series"(columns) and $n$ samples (rows), I define a return matrix $R$ of dimension $(n-1) \times k$ as : $r_{i,j}=log(\frac{X_{i,j}}{X_{i+1,j}}), \text{ } j \in ...
1
vote
1answer
57 views

avova one way vs multiway

Hello I'm running anova with R and I am wondering what the differce is between multiway anova and single anova. I know single anova gives a different answer than multiway anova but I dont know how to ...
0
votes
2answers
38 views

Question on cumulative probability

In an article I'm reading the probability of an observed point falling in bin i is written as: $P_i=\frac{m_i}{\sum\limits_j m_j}$ where $m_i$ is the number of model points in bin i. Then, the ...
1
vote
0answers
25 views

Moving average of irregular time series data using R

I'm attempting to dig out some metrics that look at how reliably clients connect to a service. The raw data is in the form of "client A, came online|offline at time X". The connection is highly ...
0
votes
0answers
40 views

profile confidence intervals in R: mle2

I am trying to use the command mle2, in the package bbmle. I am looking at p2 of "Maximum likelihood estimation and analysis with the bbmle package" by Bolker. Somehow I fail to enter the right start ...
4
votes
1answer
52 views

How to get percentage agreement between a group of factor columns?

I have a data.frame with 18 columns all of which are categorical variables containing the same factors e.g. "a", "b", "c". What I would like to produce is a matrix which is 18x18 and contains the ...
4
votes
1answer
76 views

Tracking and data association with Kalman filters

I am trying to solve tracking problem. At certain points in time I receive object location and I should make decision whether received object location belongs to existing track or not. If not, I ...

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