# All Questions

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### What is the difference between Harris Corner Detection and SUSAN Corner Detection? [on hold]

What is the difference between Harris Corner Detection and SUSAN Corner Detection
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### Conditionally remove rows that match in column A, based on column B in R using data.table [migrated]

Trying to fix a de-duplication problem using data.table in R. Column A is a list of names, some of which appear multiple times. Column B is a list of dates. There are a bunch of other columns that I ...
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### Is a normal process mean reverting

A normal process has a lot of outcomes around the mean and then fewer and fewer outcomes away from the mean. From this, can we conclude that a normal process reverts to the mean whenever it gets a ...
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### EM convergence when using em.hmm from PLIS

I use em.hmm function from PLIS package. I tried it on dimensions in range from 2 to 6. In every case of provided data (z-values) EM algorithm does not converge for dimensions 2, 5, 6. So, I wonder ...
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### difference between confidence interval and prediction interval in the context of regression analysis and predictive modeling

When building prediction models, I always see the following concept 1) Confidence interval for regression model 2) Prediction interval 3) Confidence interval for predicted value I can understand ...
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### Post-hoc after GLM: What does it exactly say?

Background: I have been asked to model the change of weight of a few animals undergoing experimentation via a simple GLM (General Linear Model). The data looks something like this. Note that all data ...
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### balls-and-urns in PyMC

In trying to wrap my head around Bayesian statistics and PyMC I've been trying to program up a balls-and-urns example. Sadly, I'm failing miserably. Assume that I'm drawing balls from an urn and know ...
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### Need clarification on a passage. (Autism Prevalence)

Passage verbatim: According to a review by Silverman et al. (2010), the incidence of autistic disorder is 0.6–1.0 percent in the population. The disorder is four times more common in males ...
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### find optimal parameters for SVM from tune() in R= [migrated]

I am optimizing the gamma and cost variable using the tune function ...
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### Square root of number of counts, or standard deviation of the mean?

I'm doing an experiment in radioactivity, where I measure the number of counts in a given time interval. I repeat 3 times and take the mean number of counts. What is a better error value to use, ...
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### Perhaps easy about SPSS Chi Square and Bonferroni

Oh hello. I just have entered here. Best place for my question. Sorry for that question in other site's part. :) So perhaps it's easy question, but I encounter this problem first time. I go ...
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### GLM - X.intercept equal to NA [duplicate]

What does it mean X.Intercept equal to NA as a result of glm summary ? Thanks. Coefficients: (1 not defined because of singularities) ...
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### Kernel matrix is a covariance function

How to prove that the kernel matrix is actually a covariance matrix?
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### Best linear unbiased estimator

I have a sample of N stocks. I have the following information: For each stock i, I have an estimate of variance (of returns) $\hat{\sigma}^2_{i}$. I also have a fitted variance, denoted by ...
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### How to bootstrap panel data?

I'm fitting some machine learning algorithms (e.g. SVM) on my panel data. It's taking too long for my entire dataset, so I'm considering generating smaller samples from bootstrapping then fit the SVM ...
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### assign asymmetric cost in SVM classification in R?

I know that we can set a symmetric cost in R for svm,how do we set an asymmetric cost? I want to do a grid optimization like the following: ...
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### Quick Exploratory Analysis of Categorical Data

Does anyone know of a tool (preferably free) that does quick analysis of exploratory data mainly categorical with date. Using R and Python I can create time series and histograms, perform tests such ...
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### In soft-margin SVM, is it guaranteed that some points will lie on the margin?

In soft-margin SVM, once we solve the dual-form optimization problem (using quadratic programming, which is guaranteed to converge on a global optimum because the problem is convex), we get a vector ...
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### Question on Stationary & Cointegration Test (Augmented Dickey Fuller & Engle Granger test)

I'm performing the stationary and cointegration test on stock prices. What I'm confused is 1) the difference between ADF stationary test and ADF cointegration test. 2) Also, in ADF stationary test, ...
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### “Dummy variable” versus “indicator variable” for nominal/categorical data

"Dummy variable" and "indicator variable" are labels frequently used terms to describe membership in a category with 0/1 coding; usually 0: Not a member of category, 1: Member of category. On ...
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### Is there any other measure of the performance of a classifier than the area under the ROC curve?

I am trying to draw an ROC curve for a classifier and wondered to know if there is any other measure for the performance of the classifier than the AUC. And is there any free software that I can use ...
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### DNA sequence classification

I have a database of 3190 instances of DNA consisting of 60 sequential DNA nucleotide positions classified according to 3 types: EI, IE, Other. I want to formulate a supervised classifier. At the ...
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### What is the “pdm” stat in the “rms” R package?

I am new to the world of Regression in statistics and I have been doing a research in which I am building an ordinal logistic regression model (ORM). In order to fit my ORM model, I am using the 'orm' ...
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### Neural Network Predicting Live Market Data (fun project for BTC prediction)

Made it just for fun - not for profit, wrote a neural network application that is predicting output from live data from exchange markets dealing with Bitcoin. Now just to clarify, i am not asking if ...
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### Acceptable values for the intraclass correlation coefficient (empty model)

I'm using xtmixed in Stata to test a Hierarchical Linear Model. My problem is that variance at level 2 is about 4% of the total variance. So most of the variance is ...
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### Probability of event happening after the last event

My question seems to be very trivial, but I'm still stuck with it. It's about probability calculations. Suppose you have a number of people that take a glass of water (event), time between 2 events is ...
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### How to reconstruct the data? [duplicate]

I have compressed the data( seven sensors are measuring 125 days temperature) using Principal Component Analysis . Then How to reconstruct the data ? What formula should i use?
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### Model Selection with Competing risks in Cox regression

When doing cox proportional hazards regression one often has competing risks. The typical approach for this is to fit separate cox proportional hazards models for each risk, censoring the competing ...
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### Benjamini-Hochberg and GEO2R

I'm currently using GEO2R to analyze a microarray data set. There is an option to generate the 250 most statistically significant genes, which calculates an adjusted p-value using the ...
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### Density of Argmax of a Gaussian Process

So I am trying to determine a density function for the argmax of a continuous Gaussian process. The only information I have available is one realization of the process and the process variance. The ...
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### Negative Binomial Anscombe Residuals

I need a help :) I'm working on a Generalised Linear Regression model, using the 'so called' NB2 model, in other words I'm using the Negative Binomial regression for count data. I would like to graph ...
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### R adds unexpected variable to interaction model

Not sure if this is more of a programming question (in which case please move to stack overflow) or a statistical model question (in which case, please read on!) I'm exploring a data set and doing ...
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### How to predict the time series data

I have no background of advanced stats. I am an engineer and I have the following data. I am representing it as a decent graph for better understanding. I want to forecast the collision for the next ...
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### Time Series Decomposition - autocorrelation of error term

I would like to do time series decomposition, but the error term has a serial autocorrelation at the end and I am freaking out because I have really no idea what to do with that. How I did it? I ...
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### Simple Code for RNN prediction using theano

I would like to use theano to implement RNN network to predict outputs given inputs. for example. given training input x = [1,2,3,4,5] given training output y = (x-1).^2 + 0.5 for the testing ...
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### Finding an area of low variance for (robust) linear regression

In order to determine a function for a Good-Turing approximation of the number $N_r$ of distinct words that occur $r$ times in a hypothetical language corpus, I'd like to run a (log-)linear regression ...
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### What is a “log-F” distribution?

Recently I have encountered the Wiener-Granger causality test. The statistic which is used is the logarithm of the ratio of two residual variances. It is well known that the ratio of two such ...
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### R: “weights” option will help calibrating class inequality?

I have a database with a binary response variable and 100 predictors (correlated and uncorrelated). I want to try the machine learning techniques in R I've been reading about in the last 3 weeks ...
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### Comparing influence of single independent variable on two dependent variables (time series)

Scenario description: Temperature has been measured at $k+2$ different depths in a borehole. Measurements of the temperature were taken once each hour over a period of about 3 months. So observed data ...
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### Marginalising over standard deviation of normal to get the posterior on mean

I am trying to understand the concepts of Bayesian data analysis by examples. I have managed to "do" something, and I would like some advise on where I have gone wrong. My data is that I have 50 ...
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### Correlation under transformation

Suppose i have a random vector $X=(X_1,X_2,...,X_k)^T$ where each $X_i$ has cdf denoted by $F_i$ . The correlation matrix of this multivariate distribution is $R_k$. Define ...
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### Expectation Maximisation Algorithm: Understand through numeric example

I am trying to learn machine learning concepts through online materials. I just studied tutorial on Expectation Maximisation algorithm. I thought one numerical example can make better understanding. ...
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### Trend analysis on time intervales

I am trying to do trend analysis on tweets. I am still confused. The classical model is based on computing the frequency of items, to say that the item with big number of frequency is the trending ...
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### poisson as an approximation to exponentially [on hold]

A motor vehicle arrive at a petrol pump having one petrol unit, in a poisson fashion and at an average rate of 10 units per hour. The service is distributed exponentially with a mean of 3 minutes. ...
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### What does an Added Variable Plot (Partial Regression Plot) explain in a multiple regression?

I have a model of Movies dataset and I used the regression: ...
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### Correlation or similarity between response surfaces

Given the dataset A and B both containing observations (x, y) whereas x can be a vector. What are some possibilities of measuring the similarity or correlation between A and B? We can assume that ...
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### Deriving the maximum likelihood for a generative classification model for K classes

In Christopher Bishop's book "Pattern Recognition and Machine learning", there is the following question: Consider a generative classification model for $K$ classes defined by the prior class ...
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### Visualize comparison of two variables with small deviation in Tableau

What is the best way to visualize following variables: distributed around some high value with small deviation? Problem details: All the deviation is concentrated at the top of the chart, which is ...