0
votes
1answer
25 views

statistical careers where you get to move around?

I'm about to get my PhD. My background is in engineering and applied mathematics. My research in statistical & machine learning methods for biological applications (without being too specific). ...
1
vote
0answers
7 views

What is the “scale” parameter in “continuous autoregressive model” in cts package?

I am trying to use the "car" command in "cts package" in R program and I see the "scale" parameter there. I wonder whether this can be assumed to be equivalent to time intervals for time series ...
0
votes
0answers
5 views

Sample Weights for classification using Gradient-Boosted trees?

How can "weights" be given to different samples according to their relative importance while using Gradient boosted decision trees for classification? How does the ...
1
vote
0answers
20 views

When is beta distribution bell-shaped?

Is there some restriction to parameters $( \alpha , \beta)$ that make the beta distribution concave down?
0
votes
0answers
8 views

GLM binomial regression in R with a mix of categorical and continuous predictors

I have three predictor variables: year (2009, 2010, or 2011), day-of-year (DOY, measured as # of days from jan 1), and vegetation type (forest or nonforest). Veg and year can be seen as categorical ...
0
votes
0answers
22 views

How to test for a significant difference between several dependent correlation coefficients?

I have a group of correlation coefficients (more than two). They are all dependent on one variable A in the form of r_A1, r_A2, r_A3....r_Ak, where 1, 2 ...k denote other variables; they all have the ...
0
votes
0answers
10 views

Feature boosting via rescaling in logistic regression and linear SVMs

If I were expressing a problem in terms of binary features, all encoded as {0,1}, could I boost some features by encoding them as {0,2}? Would the effect change based on whether I used either of the ...
1
vote
0answers
10 views

Standardizing variables at item or index level: Does it make a difference?

I'm running some multiple group CFA models comparing covariance structure by race/ethnicity and have survey data from 6th, 8th, 10th and 12th graders. My supervisor has told me to combine 6th and 8th ...
-1
votes
0answers
25 views

In R, why doesn't “rm(ls())” clear the environment? Why add “list=” [on hold]

I get that rm(ls()) doesn't work to clear the working environment. I understand that rm(list=ls()) does work. I'm looking for ...
0
votes
0answers
10 views

How to choose the training, cross-validation, and test set sizes for small sample-size data?

Assume I have a small sample size, e.g. N=100, and two classes. How should I choose the training, cross-validation, and test set sizes for machine learning? I would intuitively pick Training set ...
0
votes
1answer
19 views

Event centric clustering on R (Sports news)

i'm about to start a project on R and my goal is cluster Soccer news by event. in other words, each cluster must contain all news about a specific event from multiple sources. SO, my questions are: ...
0
votes
0answers
20 views

Proof for Sufficient and complete statistic (Shao)

Please can you help me, with this question: Let $X$ be a random variable with a distribution $P_\theta$ in $\{P_\theta : \theta \in \Theta\}$, $f_\theta$ be the p.d.f of $P_\theta$ w.r.t a measure ...
1
vote
0answers
14 views

Is there a kind of random walk process for wich the variance is a harmonic mean of the variances of compound processes?

Context: The variance of a sum of independent random walks is a sum of their variances: $\sigma^2 = \sigma_1^2 + \sigma_2^2$. In case of a dependent random walks with bivariate normal distribution it ...
1
vote
0answers
12 views

Can collaborative filtering be cast as a classical regression problem?

Having the Netflix challenge in mind: collaborative filtering is typically presented as a matrix dimension reduction. My question is how does the problem relate to classical regression (supervised ...
-1
votes
0answers
23 views

Principal component Regression Using R

Can anyone explain principal component regression with the help of an example and the code in R? How to interpret the result of a principal component regression? How to find the individual effect of ...
0
votes
0answers
11 views

Accounting for Different Levels of Twin Relatedness in SAS

I have a dataset with a number of identical twin pairs and fraternal twin pairs. I want to examine the relationship between two variables (let's call them INDEPENDENT and DEPENDENT). However, I ...
0
votes
0answers
13 views

Statistical demand forecasting

How is batch demand forecasting done in retail like in Walmart where number of products to forecast are very large in number and products are short lived i.e have less than 36 months of historical ...
1
vote
0answers
15 views

lm weights and the standard error

I am fairly new to R, but am experienced in other languages and also in data analysis in the physical sciences. I have a problem and will illustrate with a straight line fit using ...
0
votes
0answers
3 views

Measured moderator, which is influenced by an independent variable

I have a measured variable, which is found to be influenced by an independent variable (i.e., experimental conditions). I will report this in the first part of the result section. Also, as an ...
0
votes
0answers
5 views

VECM “goodness of fit” in R

I'm using ca.jo in R to perform the Johansen test on a given dataset. I obtain my VECM coefficients, cointegration rank, etc. However, it does not seem to give any notion of "strength of ...
1
vote
1answer
42 views

How to model a count dependent variable with upper limitation

I have a dependent variable, which have 0, 1, 2, or 3 for its value. I asked participants to choose three items and coded 1 if it is in a certain category and 0 otherwise. I add the three binary ...
0
votes
0answers
9 views

Include nesting factor as fixed effect in a GLMM

I have the following GLMM: success ~ age + gender + group\task + (1 + group\task|school\subject), family = binomial I want to know whether participants' probability to succeed in certain ...
1
vote
0answers
21 views

Three Events Problem Interpretation

So I am having trouble understanding what this problem is asking. (I am not asking someone to solve it but simply help interpret what the problem wants me to do.) The problem goes like this: "Let ...
0
votes
0answers
11 views

regression analysis for dataset with few predictors and few samples

I have a small pilot dataset containing experimental measurements for 12 samples, 4 numeric predictors and 1 numeric outcome variable. The goal is to obtain a first rough estimate on the extent to ...
0
votes
0answers
8 views

Zero inflated model problem: system is computationally singular

I'm using R.After getting an error asking me to provide starting values for a glm (poisson family), I took a look at my data and realized I had quite a bit of zeroes. So, I tried zeroinfl from pscl. I ...
2
votes
0answers
26 views

Cantelli's inequality proof

I am trying to prove the following inequality: EDIT: Almost immediately after I posted this question, I discovered that the inequality I am being asked to prove is called Cantelli's inequality. When ...
0
votes
0answers
7 views

Estimating Probabilities from Stratified Table

Say I have data stratified by smoking status, where $Y=1$ is has lung cancer, $Y=0$ doesn't have lung cancer, and finally $D=1$ drinks alcohol, and $D=0$ doesn't drink alcohol. How do I estimate ...
1
vote
0answers
24 views

Identifying What Causes a Variable to Increase

Say I have a dataset with several continuous and categorical variables, and I want to identify what variables (values or properties of these variables) may cause one of the continuous variables to ...
1
vote
1answer
23 views

Jaynes' Derivation of Herschel-Maxwell for Normal Distribution

I am reading the following paper: http://www-biba.inrialpes.fr/Jaynes/cc07s.pdf and cannot seem to figure out how Jaynes is deriving (P2) and below (specifically the log arithmetic ...
1
vote
0answers
24 views

Treating Categorical Data as nominal or ordinal?

There is a four category classification system for individuals with HIV, labeled Stages 1, 2, 3, and 4, with higher stages indicating more advanced disease. Cell count is a continuous variable, and ...
0
votes
0answers
7 views

computing EP messages in factor graph

I'm using infer.net for implementing a dynamic Bayesian network model. every node in each layer is dependent on all nodes in previous layer (we want to train wji, the weights of edges between each ...
0
votes
0answers
12 views

AR models on non stationary data

i am currently reading Diebold and Li's 2006 paper: Forecasting the term structure of government yields where the authors fit, albeit simple, AR(1) models on clearly non stationary data. Why is this ...
0
votes
1answer
13 views

what are the alternative open source tools for PredictionIO?

PredictionIO is good to be enough for content discovery and recommendation but it seems it does not support classification. Then I should use a different tool then Prediction IO for my prediction ...
0
votes
0answers
16 views

Formulating a Z-test (or any other suitable test ) for survey data

I have a particular survey data related to a particular job. Out of a population of 90 people in this job, 36 people are in the lowest income group. 19 out of 36 people want to quit that job. I want ...
0
votes
0answers
23 views

PCA scores and cluster analysis

I have obtained PCA scores (Anderson-Rubin) and thought to use them in cluster analysis, but have got confused how to make interpretations based on them or as what type of variable they should be ...
2
votes
1answer
118 views

Does fixing coefficients in a regression make sense, and if so how to do it?

I have a generic question about whether it might sometimes make sense to fix specific regression coefficients to predetermined values. And if this makes sense in particular cases, how do you best go ...
0
votes
0answers
16 views

Cannot get the p values from afex package [on hold]

According to this website: http://www.psychologie.uni-freiburg.de/Members/singmann/R/afex I have run: ...
0
votes
0answers
19 views

Beta and Alpha Interpretation [on hold]

I have been given some outputs as part of a group project. The model is a deterministic time-varying coefficient model weighted using a Gaussian kernel. I am ok for most of the output although the ...
0
votes
0answers
8 views

F1 score for biased binomial data

I am applying a Bayesian classifier and would like to find out the f1 score. I determined the TP, TN, FP, TP. Unfortunately I had to find out that in my cross-validation almost in all test scenarios ...
1
vote
1answer
41 views

Linear regression of 0/1 response (Fig. 2.1 of The elements of statistical learning)

In chapter 2 ESL book authors write: Let's look at example of linear model in a classification context They fit a simple linear model $g = 0.3290614 -0.0226360\cdot x_1 + 0.2495983 \cdot x_2 + e$, ...
1
vote
1answer
9 views

beta differs from overall subgroup

I want to know whether the beta of a subgroup differs from the beta of the overall group. Both variables are dummy variabes. The overall group variable has 52 out of 267 obseverations where it takes ...
1
vote
0answers
17 views

Kalman Filter to correct model simulation bias

I am working with a large scale deterministic model, which attempts to simulate CO2 emissions in different regions. When compared to historic data, the model output suffers from systematic biases. ...
0
votes
0answers
8 views

In R and INLA, how do I graph results of 'rw2' model?

I'm working with model 2 of INLA's Zambia example in R: ...
0
votes
1answer
21 views

How to include noise in clustering evaluation?

When evaluating clustering methods which do have a definition for noise points (like dbscan), how noise will affect evaluation? Consider a clean dataset like well known Iris dataset. There is no ...
4
votes
0answers
18 views

prediction interval of a new prediction out of a weighted linear regression model

This question is based on the example 11.1 out of the book Applied linear statistical models of Kutner, Nachtsheim, Neter and Li. You can find the data here. First they calculate a simple linear ...
0
votes
1answer
27 views

What is the difference between the Mann-Whitney and Wilcoxon rank-sumtest? [duplicate]

First of all, what is the difference between the Mann-Whitney and Wilcoxon rank-sum test? How do I choose between the two? I know the latter is implemented in R, is there a way to do the Mann-Whitney ...
1
vote
0answers
32 views

How to customize a link function to perform a logistic regression?

My data was collected using Randomized Response Technique. So I have additional variability into the data. I need to use a GLM (logistic regression) but I should customize a logit link function to ...
0
votes
0answers
21 views

A question about warning that performing k-fold CV with caret

I am trying to createFolds function in caret to use k-fold cross-validation in R. But I came across this warning: ...
0
votes
0answers
11 views

Under-forecasting in Regression

I have to do forecasting of sales that is how much sales of a product is going to happen in a particular store. I have time series data for last two years and doing forecasting for 2014. The variables ...
1
vote
0answers
3 views

scale of measurements in sign test and signed rank tesr

Can some one help me to understand the right scale of measurement to use in sign test as well as in signed rank test? I read a certain book it says nominal scale is used in sign test while ordinal ...

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