# All Questions

20 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 ...
4 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 ...
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 ...
48 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 ...
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 ...
25 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 ...
12 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 ...
10 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 ...
28 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 ...
9 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 ...
38 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 ...
25 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 ...
54 views

### Treating Categorical Data as nominal or ordinal? [duplicate]

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 ...
32 views

### Bayes' classification in R

For a machine learning class I am taking, on our first homework assignment we are given the following problem that has me stuck: ...
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 ...
14 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 ...
15 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 ...
17 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 ...
27 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 ...
121 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 ...
18 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: ...
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 ...
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 ...
43 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 $g = 0.3290614 -0.0226360\cdot x_1 + 0.2495983 \cdot x_2 + e$, ...
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 ...
20 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. ...
9 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: ...
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 ...
20 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 ...
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 ...
52 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 have a binary response variable. Should I customize a logit link function to incorporate ...
22 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: ...
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 ...
4 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 ...
15 views

### Regression with covariates on time-series data [on hold]

I have monthly data at physician level (sales and marketing activity data for last 12 months for 3000 physicians). I want to find out the impact of marketing activity on sales. There are other ...
9 views

### Record Linkage Using Fellegi-Sunter Model

I am trying to create a record linkage system using the fellegi-sunter model.I am following this paper http://digital.library.okstate.edu/etd/SHIN_okstate_0664M_10668.pdf. I am not understanding ...
21 views

### multiple imputation for categorical data question

How do i design the use of Multiple Imputation based on Bayesian Inference when I am dealing with categorical data and my dataset does not contain complete prior observations at every combination ? ...
10 views

### Parameter Estimation for Naive Bayes - Maximum a posteriori and Maximum Likelihood

I am wondering if I understand those terms correctly. To summarize my thoughts: In naive Bayes, our decision rule is basically the Maximum a posteriori (MAP) estimate of our hypothesis. We assign an ...
21 views

### Interaction in regression [duplicate]

In my regression model of BMR on age (yrs) , gender (1=male, 0=female), height and weight. The regression equation obtained is: BMR = 1232.059+13.281 weight+3.954 age+192.214 male-3.471 age:gender. ...
25 views

### How to compare two clusterings generated by two clustering approaches

I am currently working on a modification of a clustering algorithm to suit my problem domain. I want to know which methods are available for me to compare the centroids generated from the two ...
18 views

### how to compare groups and percentages within

I am new to statistics and would really appreciate help. The people within the groups are different - how do I compare the percentages to see if there is a statistical significance between the groups ...
95 views

### How to represent categorical data in a pie graph form?

I have been asked to produce a pie graph of some categorical data. On a simple scale it look like this: ...
13 views

### Determining whether a dataset can be forecasted

Given a dataset $D$ representing past history of a certain variable, is there a metric $\alpha(D)$ which determines whether the dataset can be forecasted or not, i.e. $\alpha(D)$ tells us whether $D$ ...
10 views

### How can i see whether my Restricted Boltzmann Machine learnt proper or not

I am training Restricted Boltzmann MAchine with MNIST Datasets. As per my understanding if it can reconstruct input proper then i will say it learnt. But, when i use Persistent Contrastive Divergence, ...
12 views

### R programming: Lapply(split) and Model Generation [on hold]

I would like to generate and store for multiple models to subsets of my data, but am having a hard time getting the programming code to produce correct output for more than one model. I have hundreds ...
28 views

### Graphing the usage of legal precedents

I would like to hear recommendations on what tools to use to graph the usage of precedents in a legal court in Brazil. The data is searchable at www.stj.jus.br/SCON/, and in the most recent collegiate ...
12 views

### Equivalence in model performance metric like RMSE

I am calculating the root mean squared error (RMSE) to compare the simulated values of a model with the corresponding observations. I have three observational datasets. The number of data points in ...
13 views

I am trying to follow up the example code in the "Building Predictive Models in R Using the caret Package" paper from Max Kuhn[1]. Here is the part of the code: ...