# All Questions

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### How can I calculate a confidence interval for true mean of one set being higher than another, based on samples from each?

I have two sets A and B each containing N elements and want to show that the true mean of A is less than that of B with certain degree of confidence. (Specifically, the sets represents items of "yes" ...
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### Research on debt recovery

My final year project is on debt recovery data for a debt collection firm. Data such as original/current balances,payments made,DOB, number of contacts made,whether or not a debtor has made insuarance ...
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### Differences in SVM performance

Why would a polynomial SVM have better performance than a linear SVM but the same performance as a radial SVM?
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### Mean and single prediction bands for custom nonlineal CDF in Mathematica

I have a CDF obtained with the code: ...
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### Transforming data for canonical correlation analysis

Okay, I'm a stats newbie so I'll try to be as specific and clear as possible. I have a set of predictor variables (2 predictor variables) and a set of response variables (7 response variables). I am ...
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### Using OLS for Model Selection and Prediction - Heteroscedasticity Issue

I am new to regression and having problem in solving Heteroscedasticity in OLS. Have done lots of homework and test before seeking your advice. Sharing the background and what I have done to solve the ...
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### Predictive modeling techniques for in-sample rather than out-of-sample prediction?

Is it appropriate to apply predictive modeling variable selection and shrinkage techniques (for example, ridge regression or lasso) for in-sample prediction rather than out-of-sample prediction? ...
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### SVM and kernels

Suppose you are given a binary classification problem. How do you know that you have to map the problem into a higher dimensional space? In other words, how would you know that a linear SVM is not ...
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### About cross-validation for machine learning

Assume I have 1000 samples of data. I split the data randomly into training and test sets of size 800 and 200, respectively. Now, I train a classifier using the training set, and then evaluate the ...
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### If $X \sim$ unif$(0,1)$, what is the distribution of $U=\max \{X,1-X \}$?

Let $X$ be uniformly distributed in $(0,1)$ and set $U=\max \{X, 1-X\}$. How can I find the distributiopn of $U$? My first thought was to consider this a mixture distribution problem and use the CDF ...
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### Find the effect of a attribute value on an outcome by eliminating confounding values

I have a series of lets say five attributes. The first attribute is called diagnosis code 1, the second diagnosis code 2 etc. The values are codes which represent diseases. In other words, each ...
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### interpreting my own data (negative confidence interval in epidemiology)

Im trying to measure the absolute change between two means of systolic bloodpressure, and used a simple method for calculating the confidence interval between to means. My goal is to estimate the ...
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### One sample Hoteling's T2

I used one sample Hotelling's T2 statistic to check if the nutrient intake of 75 men meet the recommended daily nutrient intake value. I got an F value close to 58000. Is such a large value ...
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### Is there a significantly different number of people between groups?

How do I estimate whether a given number of people across groups (say, 72 people in group 1, 95 in group 2 and 70 in group 3) significantly differs from a random distribution of people across groups? ...
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### K means cluster analysis

I used two variables height and weight and using K (=2) means cluster analysis 2 clusters were obtained. I used k=2, as the observations either belong to men or women. I then compared the obtained ...
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### How to calculate prediction intervals in major axis regression using R

Need help in calculation of prediction intervals in major axis regression (MA). I'm using 'lmodel2' package for calculation of the MA, but I don't understand how to calculate prediction intervals ...
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### the Dempster-shafer theory [on hold]

I want to use dempster-shafer theory to compute certain threshold. I want to ask you if someone have documentation or suggestion about this problem. thank you
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### How many samples do I need to prove that a classification algorithm is better than another?

I have two algorithms A and B, used to automatically classify each of N elements into K categories, N and K both being in the millions. Neither A or B is perfect, but it is relatively easy for a human ...
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### Interpretation of two indexes Interaction Term

Respected Fellows. I will thankful if someone help me to explain my model results.my model is as follows. Yit=αPFit+βPSit+δ (PF*PS) it+εit Where Y is GDP per capita PF=Political Freedom Index ranges ...
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### Which Test to Use?

I was wondering if someone could help me regarding the statistical tests I should use. Basically I have the following: 1) I carried out a survey asking teachers and students to rank components in my ...
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### How to use Hartemink's discretization algorithm?

From the help documentation of the discretize function of the R package bnlearn: Hartemink's algorithm has been designed to ...
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### Why does maximum likelihood estimation not work in estimating signal in deterministic chaotic noise

I have few conceptual questions related to application of chaos in communications. In few application such as radar Chaotic signal reconstruction with application to noise radar system, cryptography, ...
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### How do I estimate a time series regression using GMM in the way proposed by Acosta-Ormaechea and Morozumi (2013)?

In their paper Acosta-Ormaechea and Morozumi (2013) propose a use of GMM for estimating a regression in which they try to find the impact of reallocating public expenditure from some unproductive to ...
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### Estimating workers within Industry Sector using commuter data (combining probabilities?)

I have some detailed data about the commuting patterns of workers. If I know the following 3 things... The total number of workers commuting from one block to another. The total # and % of ...
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### C-Test for comparing poisson means in Scipy

I'm relatively new to stats, and I have a large dataset of strings (n=114541) for which I'm interested in a binary event: whether X occurs or not (specifically, whether a specific language construct ...
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### Calculating upper and lower confidence limits on a population estimate derived from multiple point estimates

I am generating a river reach population estimate for a freshwater mussel by summing point estimates made across a gridded point network (within the reach) using a generalized linear mixed model ...
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### Have conducted a bivariate correlation - want to identify the outlier - is there a 'statistical' way to do this?

I run correlation (on SPSS) between a governance indicator 1996 and the same governance indicator in 2012. As would be expected there is a near perfect correlation. What I am interested in, however, ...
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### Neighbours list extracted out of polygon regions [migrated]

I've got a SQL database which contains some coded polygon structures. Those can be extracted as follows ...
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### How odd is a cluster of plane accidents?

Does this quotation from the news media make sense, or is there a better statistical way of viewing the spate of recent plane accidents? "However, Barnett also draws attention to the theory of ...