0
votes
0answers
6 views

Difference between significance and contribution

"What is the difference between "significance" and "contribution" of individual variable to a outcome variable? How to address this while creating a prediction model basically.I understand ...
0
votes
0answers
5 views

Matlab GUI background color changing to black when using parallel computing for MLP and SVM

I designed a GUI in Matlab that uses parallel computing in loops for accelerating speed. When I disable parallel computing everything Is normal but when I activate it background color of my GUI and ...
0
votes
0answers
6 views

What is $C_{pk}$(test) $-\ C_{pk}$(reference)?

I have a process under test (approximately normal distributed), and I have calculated $C_{pk}$ (a process capability index) for this process. These values are compared to reference values which are of ...
1
vote
0answers
7 views

Extremal serial dependence

As part of my analysis of heavy-tailed time series of company returns, I would like to check whether extreme returns exhibit serial dependence, i.e. if extreme events are followed by extreme events. ...
0
votes
0answers
11 views

How to calculate sample size?

I need to know how many people of risk group do I have to screen, to get any statistical significance? For example renal cell carcinoma is diagnosed to 25 people from 100 000 population. If they have ...
0
votes
0answers
9 views

Interpreting CCF correlation in R

I am using ccf to find a correlation between 2 time series. I am getting a plot that looks like that: Note that I am mainly interested in correlation for the ...
0
votes
0answers
9 views

Can a growth model of diseases incorporate vital signs data?

I intend to study the growth rate of diseases among patients of different age groups (cohorts) and comment on the growth of diseases in the next 5 years. Can I incorporate vital sign readings such as ...
1
vote
0answers
7 views

Using an odds ratio when data is sparse

Suppose I have around 20 exposures that potentially affect an outcome and I want to see which exposures have bigger impacts on the outcome. So I want to calculate each exposures' odds ratios by ...
0
votes
0answers
16 views

what percentage of total variables can be captured in a prediction model

I need to create a model with 45 explanatory variables. As per industry norm, what is the maximum percentage of variables that can be selected for creating a model? Thanks
0
votes
3answers
17 views

Can you set a minimum limit for the Y-intercept in R?

I have two sets of test scores I'm using to predict future performance, using multiple regression, and I noticed that the y-intercept is negative. This indicates that for a student who scores a zero ...
-1
votes
1answer
23 views

How to capture & present lm model output from R

After running iterations of lm() in R, I am now stuck with which components of the model's output to present and how to present them. I know that the r-squared ...
-2
votes
0answers
19 views

What´s the fastest SVM library for C#

I want trainning my nets faster. I´m using KMLib (not GPU), but the speed is not so good. My problem is a classification one.
0
votes
0answers
7 views

Model creation under PLS

I'm developing prediction model based on PLS analysis. I'm looking into variation captured by X(R square X), R square Y, number of components and accuracy after using cross validation, in the process ...
0
votes
0answers
8 views

Rule of thumb about how many data points are needed to train a GMM

I have about $10^6$ data vectors, each with 13 dimensions. I'm trying to train a GMM of 256 components using EM algorithm (using GMMBAYES). Is there any rule of thumb about how many data points are ...
0
votes
0answers
3 views

Applying Cox proportional hazards model to new data to get absolute risk (Framingham risk score)

I'm trying to apply one of the Framingham cardiovascular event risk scores to a new dataset in order to get absolute risk. D'Agostino 2013 "Cardiovascular Disease Risk Assessment: Insights from ...
0
votes
0answers
9 views

Do I need to care about constants in Expectation Propagation

I am trying to approximate a certain factor in my graph. Following Tom Minka's tutorial what I have to do is as follows: $$ \prod_{i=1}^3 q_{w_i}(\pi_2)\approx \int ...
1
vote
0answers
21 views

How to evaluate the fit of a logistic regression

I have a set of data points, which exhibit a solid linear correlation $r\approx 0.9$. I am basically plotting population in certain areas against the number of occurrences of a certain phenomenon (in ...
0
votes
1answer
13 views

Graphical Model Equivalent of Matrix Pseudoinverse

The may sound like a strange question but I was wondering if a Pseudoinverse of a matrix could be found using SVD whether there was a graphical modelling equivalent that could be used to estimate the ...
1
vote
0answers
10 views

is it possible a nonstationary time series, to produce a stationary ARMA model?

I Have a variable (time series) which is nonstationary. I found that from the graph which seems to have a stochastic trend and the correlogram has a typical nonstationary pattern. After that, I've ...
1
vote
0answers
10 views

Only binary predictors — ANOVA, regression, or other?

I am trying to fit a model to predict a quantitative response variable, using several binary variables. In particular, I am interested in measuring the relationship between one of the binary variables ...
6
votes
1answer
27 views

Real examples of Correlation confused with Causation

I'm looking for specific, real cases in which a causal relationship was inappropriately inferred from evidence of a correlation. Specifically, I'm interested in examples that meet the following ...
0
votes
0answers
5 views

Datasets for market segmentation

What are the gold standard datasets to test market segmentation algorithms with? I'd like to try a few algorithms on known datasets for comparison before I try my own dataset.
0
votes
0answers
5 views

Bootstrap confidence bands for time series data

I have time series data for 30 people. The data is knee joint angle versus percent of gait cycle, with data at every 1% of the cycle. I can easily find the mean joint angle at every 1% of the gait ...
2
votes
0answers
16 views

How do I investigate how long it takes one variable to affect another in a time series

I am a total newbie when it comes to time series, so it is quite possible this question is duplicated somewhere else, only that I cannot find it because I don't know what this feature is called. My ...
-1
votes
0answers
7 views

calling weka classifier in matlab with cossValidateModel

how can we call weka classifier in matlab with cross validation? what parameters we can pass to crossvalidatemodel in matlab. weka.classifier.Evaluation.crossvalidatemodel()???
4
votes
3answers
83 views

Determination of regression model

I would like to regress total energy expenditure on age, gender, height and weight.But how do I check whether this relationship is linear?
1
vote
1answer
29 views

Is there such thing as correlation trees? Clustering rows of X based on correlation between A and B

I have been searching for several days for a method that fits this description, though cannot find one. I'm pretty sure it must exist. The problem (short version): I'd like to run something like a ...
1
vote
1answer
19 views

ROC/AUC Confidence Interval

For a single ROC curve (with relevant AUC score), how can you calculate the confidence interval? (The data used to generate this ROC/AUC is available) Given my relatively limited background in this ...
0
votes
0answers
14 views

Dynamic pricing optimization of function in R

I'm working my way through a simple dynamic pricing model, and I'm having trouble figuring out how to optimize what I'm working on. I want to maximize $\Sigma_{t=1}^TR(D_t) - h_tI_t$ for the ...
0
votes
0answers
6 views

Weighted training in Adaboost

I am learning the Adaboost algorithm, but I am finding difficult on understanding this concepts (I am using the notation of the paper of shapire): What does it means 'Train base learner using ...
0
votes
2answers
28 views

Count event using Poisson random variable

An event occurs with a mean of 15 times per hour and a standard deviation of 10 times/h. From the population a sample of 100 individuals is drawn. What is the probability that the sample mean will be ...
3
votes
1answer
15 views

Notation: Deterministic Variable, Random Variable, Realization of Random Variable, Function

Is there a standard notation for distinguishing between the following: Random Variables Realizations of Random Variables Deterministic Variables (not random) Functions I am familiar with using ...
-2
votes
0answers
34 views

I need help about my statistics homework [on hold]

The average number of mosquitoes in a stagnant pond is 60 per square meter with a standard deviation of 16. If 9 square meters are chosen at random for a mosquito count, find the probability that the ...
-4
votes
0answers
21 views

I need help finding the variance for this problem [on hold]

Find the variance for the values of n and p when the conditions for the binomial distribution are met. n=700 p=.85 a. 89.25 b. 595 c. 9.4 d. 105
0
votes
1answer
14 views

Confusion between caret randomForest predict() results and reported model performance

This question seems related, but the consensus was that the issue had to do scaling the data, which I do prior to training, so I don't think that's the issue: Issue on prediction with FinalModel of ...
1
vote
1answer
18 views

What is the difference between ex ante and a priori, if any?

In the context of estimating geophysical quantities from remotely sensed data (inverse theory), what do the terms ex ante and ex post mean? For context, see for example this paper by T. von Clarmann ...
0
votes
1answer
12 views

R - Test for homogeneity of regression slopes results in singular model

I am trying to check the assumptions of a two-way ANCOVA. So in my model I have two factors (F1, F2) one dummy coded two level covariate (C) one dependent variable (D) In order to check the ...
9
votes
3answers
472 views

What is your favorite statistical graph?

This is a favorite of mine This example is in a humorous vein (credit goes to a former professor of mine, Steven Gortmaker), but I am also interested in graphs that you feel beautifully capture and ...
2
votes
2answers
14 views

Dimensionality reduction (PCA) for plotting text documents on a graph

I have 50 text documents There are 500 possible words, after a stop list has been applied My term/document sparse matrix is therefore 50x500 I'd like to cluster these documents. One easy way to do ...
0
votes
0answers
18 views

10 fold cross validation model in weka

down vote favorite I am new to Weka. Trying to build a specific Neural Network arcitecture and testing it using 10 fold cross validation of a dataset. Now building the model is a tedious job and ...
0
votes
0answers
12 views

Standardizing before/after/at all when using multi-class LDA for pre-processing step

If a multi-class Linear Discriminant Analysis (or I also read Multiple Discriminant Analysis sometimes) is used for dimensionality reduction (or transformation after dimensionality reduction via PCA), ...
0
votes
0answers
12 views

Number of Predictors and Classification Algorithm

In general, is it better to include more predictors in algorithms such as SVMs and random forests compared to logistic regression? It seems that when we add more predictors to logistic regression, the ...
2
votes
0answers
16 views

How to approximate error on Chi-Squared Fit when bin counts are zero

I am using a galaxy image simulator that provides a 2D histogram that has the number of photons per pixel (bin) $N$. I am currently using a least-squares residual: $\sum_{bin}(f_{data}-f_{model})^2$ ...
2
votes
0answers
19 views

10% dip in February for metrics that count?

February usually has 28 days, unlike it's neighbors January and March which have 31. It seems that most countable things will exhibit, on average, a 10% dip in February for the missing 3 days. This ...
2
votes
2answers
32 views

Should I perform multiple t-test or an ANOVA?

My causal comparative study seeks to three questions related to the hypothesis: a) is there a statistically significant difference between the academic achievement of 6th grade mathematics students ...
0
votes
0answers
9 views

Meta-analysis in R with multiple probes of a microarray

Regarding a question posted here, I have the same problem and I can't figure out a solution. I started by doing my meta-analysis in PLINK, but I want the confidence intervals of the meta-analysis, ...
0
votes
2answers
18 views

Overall Significance vs. Individual Variable Significance in Mutliple Regression

I'm running a statistical analysis for work in which I'm trying to determine which (if any) key economic indicators influence our sales. Here is the summary data that I'm getting when I run a ...
0
votes
4answers
28 views

Two groups are significantly different? Test to use

I have two groups of discrete data (integers): ...
0
votes
1answer
23 views

Compare coefficients from two separate panel regressions in Stata

I am trying to compare the coefficients of two panel data regressions with the same dependent variable. What I am aiming at is the following: ...
0
votes
0answers
16 views

center variable separately for each factor in linear mixed model?

I am working on a relatively simple mixed model where I have two continuous predictors with an interaction term and three sites. I am treating the two predictors as fixed effects and the site as ...

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