0
votes
0answers
22 views

Corresponding SAS mixed model in R [on hold]

I am looking for the corresponding R model for the following SAS model. ...
2
votes
1answer
15 views

Why not using the R squared to measure forecast accuracy?

Why in literature usually the common accuracy measures like MAD, MSE, RMSE, MAPE ... are used. Why not using the R squared (coefficient of determination)? I was thinking about the difference: By ...
1
vote
0answers
16 views

lme4 in R: how to specify 2 correlations with random intercept, without adding correlations between random slopes [on hold]

I am trying to specify a model in R's lme4 package in which I have 2 correlations between random intercept and random slopes, but the random slopes are not allowed to correlate. ...
2
votes
0answers
14 views

Detecting discontinuities in irregularly-spaced data

I am running physics simulations. Sometimes a simulation has insufficient resolution and produces discontinuities in the output variables. These are very easy to spot by eye in a scatterplot. I would ...
2
votes
0answers
9 views

Are there any open-source implementations of structured prediction methods? [on hold]

I'm currently interested in structured prediction field. I've looked around the web but haven't found any implementations of this kind of algorithms in any of languages. Have I not searched enough or ...
0
votes
0answers
31 views

Multivariate normal value standardization [on hold]

I am wonder how to standardize multivariate normal value and check that standardization gives correct result. This question is copy of mine from math section where I get no answear or idea about the ...
0
votes
0answers
17 views

How to calculate test information in computerized adaptive tests

Under Item Response Theory, test information $I(\hat\theta)$ is a function of the examinee's estimated ability $\hat\theta$, discovered a the end of the test, and the items that were answered during ...
0
votes
0answers
16 views

Is this data really detrended?

I have a time-series vector for a macroeconomic indicator, which clearly has trends, when I apply the detrend method of matlab, I see a change in the ...
-1
votes
0answers
24 views

Interpretation of coefficients in per capita terms [on hold]

I come across an article with a regression output: $y=-53,06+122,58x-200,7x^2$ $y$ is here total spending and $x$ is the ratio of people receiving benefits (of total population). The mean of $x$ ...
0
votes
0answers
10 views

How to calculate BIC for K-Means to get best K

I'm really new to K-Means clustering technique. I'd like to calculate BIC for K-Means to find best K (number of clusters). I looked around on the web to find a solution in python but there is no ...
0
votes
0answers
18 views

How can I estimate weibull parameter in R? [on hold]

I'm new user of R. I have quantal response data with sampling test. Before sampling test decide sample size and sampling points. This data is test with '75' sample size and '20'sampling points. ...
2
votes
0answers
8 views

Computations of Durbin-Watson quantiles

For some educational reasons I am currently trying to re-compute Durbin and Watsons (1951, Paper II) critical values of the lower and upper bounds of their Test-Statistic (dL and dH), and also table ...
0
votes
0answers
27 views

Find best K value for K-Means clustering [on hold]

I'm doing the K-Means clustering for my data. Following python script does K-Means for 2 clusters. ...
0
votes
0answers
12 views

Cronbach's alpha internal consistency test for interval scale or ratio scale data with different units

I have recently read dos Santos, S. F. & Brandi, H. S. 2015. Model framework to construct a single aggregate sustainability indicator: an application to the biodiesel supply chain. Clean ...
0
votes
1answer
16 views

Variables in the regression

Would it be correct if the outcome variable is at the household level, to use variables at both household and household member level as regression explanatory variables? E.g. if the outcome variable ...
0
votes
0answers
12 views

Relation between P chart and Chi-square test

P chart checks whether a manufacturing process is in control with respect to the proportion of non confirming items and Chi-square test for homogeneity tests whether several populations are similar or ...
0
votes
0answers
11 views

Normalization in R before doing PCA [on hold]

I have a dataset as a .CSV file (a 70*12 matrix) I've givven it to R as Input data! Now , I want to do PCA on it. But , I should standardize (normalize) it first brfor doing PCA. But I do not know ...
0
votes
0answers
7 views

Comparing distributions against expected to determine the best fitting

I have a 4 sets of observed absolute frequencies for a categorical variable and the expected frequence for each category (not normal distributions). Would it be correct to use the Chi-square goodness ...
0
votes
1answer
28 views

Metropolis, simulated annealing and proposal distributions

I'm trying to understand the physical meaning of the proposal step generating function in Metropolis algorithm. In the original paper, and most derivations I found, it seems that it's not much ...
0
votes
0answers
7 views

marginal effects and total effects in regression with interactions

I have a question that seems very simple and yet I need a final push to lock up the intuition in my head. I am running a regression that can be simplified to look like this: log(wage) = $\beta_0$ + ...
2
votes
0answers
23 views

How to predict & plot quasipoisson GLM in R

I have a set of complex survey data with sampling weights. I am using the svyglm() function from the survey package in R to ...
3
votes
1answer
20 views

Duplicate Training Data in Decision Tree Learning Algortihm

I have the following training data set where the first line shows the name of attributes. ...
0
votes
1answer
18 views

How to calculate distance between 2 lists in r with only general attribute information? [on hold]

I need to calculate distance between two simple lists in R and would like a little logic help please. The issue is that I do not have a data set, rather just a range for each attribute. Here's what I ...
0
votes
0answers
7 views

Measuring the uncertainty of the average of average rates

Is it possible to determine the mean value of a point by averaging the average rate of ranges that contain that point, and if so, how can the uncertainty of that value be accurately determined? I ...
1
vote
1answer
17 views

Incorrect class displayed when using 'apply' function in R [on hold]

I see a problem with the apply function in R. 1. This does not show the right class. ...
0
votes
0answers
16 views

Rules for choosing how much training data one needs to learn a Radial Basis Function model?

I was trying to understand how much data I would need compared to the number of parameters (and to have good generalization) when I train a radial basis function (RBF) network on a regression task ...
1
vote
0answers
10 views

Blocked Gibbs Sampling using Forward / Backward Algorithm

I am new to machine learning and have been reading about gibbs sampling. From my understanding, gibbs samples a single variable iteratively conditioned on all other variables. In blocked gibbs ...
0
votes
0answers
26 views

State space model affected from future events?

I understand that a state-space model is a common model where the current observation $y_t$ depends on the current state $x_t$. Is there any common model where the current observation $y_t$ depends ...
0
votes
0answers
12 views

How to find a linear dependency in a 2-D histogram?

I have a matrix (average of several trials), with x and y as independent variables, and z as dependent variable. It can be plotted as a 2-D histogram. Now I want to detect if there is any significant ...
1
vote
1answer
21 views

What does the acf of the log of data tell us?

I'm working with time series data. And there is a use of acf ( auto correlation function ) being applied to the log of a ...
1
vote
0answers
19 views

How find confidence regions for multivariate ( or at least bivariate) distributions other than Normal

I am looking for a method which is able to find confidence regions in multivariate distributions with $(1-\alpha)\%$ probability of occurrence. What I mean by probability of occurrence is that, the ...
0
votes
0answers
16 views

How to check if two results are consistent

I'm looking at an astronomical object. In one observation, it does something (not relevant what :) 2199 times out of a possible 2936. In another (later) observation, it occurred 2094 times out of a ...
2
votes
2answers
28 views

Is the probability of being diagnosed HIV positive given the positive test dependent of the incidence rate (p)?

after seen this example, I've a doubt. Is the probability of be diagnosed HIV positive given the positive ELISA reading dependent of the incidence rate (p)? Why should it be? $$P(\text{HIV positive ...
3
votes
1answer
33 views

Prove that maximum likelihood estimators for Gaussian distribution are a global maximum

I'm studying on Casella-Berger, I'm at page 322 in which it explain how to find MLE for a Gaussian distribution with parameter $\mu$ and $\sigma^2$, both unknown. It finds MLE, and up to this point it ...
1
vote
1answer
21 views

How to derive the probability function from information entropy?

How to derive the probability function from information entropy? $H(X)=\sum P(x_i)I(x_i)$ $H(X)=\int P(x)I(x) dx$ Can we get the equation in the form of P=f(H)?
0
votes
0answers
12 views

Is it an ANCOVA?

In a study, baseline pulse is recorded. Participants are asked to watch a funny video and a thrilled video for 10 minutes. Pulse is recorded again. The objective of the study is to investigate ...
2
votes
0answers
20 views

Is there a goodness of fit measure for Survival Analysis (Cox Regression) if there are late entries?

I am running a Cox Regression which includes some late entries (left censored). The subjects simply did not exist at the beginning of the analysis. Harris' C & Somer's D don't work for such data. ...
0
votes
0answers
7 views

How to apply a model on dataset with missing data?

This question is similar to Missing input value during prediction of a generalized linear model. Consider the following scenario: I fitted a linear regression model on a training dataset with ...
0
votes
0answers
12 views

How to choose between data-driven pattern or intuition?

I am performing a multivariate logistic regression (This could very well be any other kind of regression method) to study the effect of some predictor variables on the probability of event. I have ...
0
votes
0answers
32 views

Looking for the best data analysis

I am currently in my dissertation phase and I am stumped on what data analysis I should be using. I am looking to evaluate resilience differences in genders. I'm using a non-experimental, causal ...
1
vote
0answers
12 views

Fitting mixture distributions and probability estimation

I am working on continuous data set with ranges 0-1. I need to group them using mixed models (based on prior clinical/biological basis). From this model, I need to get the p-value for a value (say ...
4
votes
1answer
29 views

What are the prerequisites to start learning Bayesian analysis?

Or in other words, How mature-I mean my statistical knowledge- should I be to start learning and doing Bayesian analysis?
1
vote
0answers
9 views

Unit root: differencing vs. using % change vs. taking ln

Let's say your trying to forecast a country's GDP with an ARMA model. Obviously the original series will contain a unit root (at least most of the time), so which series would you use the model on? Is ...
4
votes
1answer
43 views

Looking for the distribution of the difference of two Gaussians in a weird relationship

I have a covariate $B$ (let's say age) and two different responses $T_1$ and $T_2$. The bivariate distributions of $B,T_1$ as well as $B,T_2$ are bivariate normal and known: $$ ...
0
votes
0answers
6 views

Comparison of Clusters with the Aggregate [on hold]

Just wanted to know if there were any good tests/measures that compare a cluster to the aggregate data. So suppose that I already have clustered/partioned data $x_{i,j}$ (data point j in cluster i). ...
0
votes
0answers
8 views

K-means or Relative Risk - which method is takes more computation

We are trying to solve a decision around modelling perform for destination grouping. We have a large set of destinations (>500k) selected by a set of guests and would like to cluster them together ...
1
vote
2answers
23 views

Corresponding RKHS of Common Kernels

A kernel, $k(x_1, x_2)$, has the interesting property that it may be represented as the dot product in a reproducing kernel hilbert space (RKHS), $\phi(x_0)\phi(x_1)$. I know that for the gaussian ...
0
votes
0answers
4 views

How to plot identical slopes for an ANCOVA (1 categorical variable(2 levels) with 2 covariates) using ggplot2

I am trying to compare and plot regression lines of an ANCOVA when their slopes are the same and no interaction effect There are two sets of ANCOVAs plots that I am trying to create: a) 1 ...
3
votes
2answers
27 views

Probability of 3rd card between 1st two

From a random deck, 1 card is drawn, then another. Then without replacement a 3rd card is drawn. What is the probability that the 3rd card is between the 1st two.
0
votes
0answers
13 views

Visualizing Sample Size Calculation for Longitudinal Time Series Data

I have a data set consisting of 500 individuals and 36 observations for each (3 years by month). The values consist of each individual's maximum daily consumption for that month. The population is ...

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