# All Questions

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### How can I model random graphs (trees) with deterministic constraints?

I have been trying to represent a tree structure as a random graph, but so far my research has led to variations of random graph models and I can't see studies which may help me leverage some of the ...
8 views

### Population stability index - division by zero

Population stability index quantifies the change of a distribution of a variable by comparing data samples in two time periods. It is very commonly used to measure shifts in scores. It is calculated ...
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### Comparing two means with same sample size

I am trying to do some web statistics (AdWords). I have a cost, a revenue, and a number of clicks. How do I determine if the difference between cost/click and revenue/click is statistically ...
17 views

### What are the dangers of using a (log)normal distribution for a discrete response?

I have seen in the engineering field some papers (one example) using normal or lognormal distributions to model discrete outcomes. Typically, the explanatory variable is binned (into equal intervals) ...
28 views

### In what situations is covariance preferred to correlation?

If the magnitude of covariance doesn't really convey any reliable information, and correlation provides us the same information but also gives the degree of dependence, then why use covariance at all ...
8 views

### Significance test of the AVERAGE of some point measurements (non-gaussian)

Say, I have the following point measurements (98 samples) (copying from R console)- ...
27 views

### Metropolis algorithm, what is the target distrbution and how to compose it?

When do Metropolis sampling or MCMC, we need a target distribution $P_{target}(\theta)$, and a proposal distribution $P_{proposal}(\theta)$, then a value $\theta_i$ is generated via ...
32 views

### Why we need for detecting and removing outliers?

Suppose we use some time series (rainfall) data and some outlier detection methods for detecting outliers. In this situation If we remove the outliers, then what are the causes affected by the ...
13 views

### Statistical Tests for comparing groups

I am a biologist and I have developed an algorithm that has the ability to identify and quantify fluorescent objects within the nucleus of a cell when imaged in a fixed state under a microscope. The ...
16 views

### Model estimation procedure using backward elimination

I have run a multiple linear model using Minitab. The result showed that all variables are not significant. So, I use backward elimination. Lastly, I found that ...
14 views

### Model specification

Actually I want to see the impact of Investors sentiment on Aggregate stock market return, so my major concern is to identify the impact of investors sentiment. But besides investors sentiment I want ...
17 views

### given mean and standard deviation, find value of given percentile

I'm running a DnD campaign and made a Random NPC generator in Excel. It's pretty slick, but the random height/weight calculator is... flat. RAND(X,Y) flat. So I'd like to add some Bell Curve ...
10 views

### Proper splitting of data set for Ensemble methods

I have 10,000 documents. Each document has a label ($Y$) that is either $0$ or $1$ (the 0-1 split is pretty much 50/50 over my 10,000 documents). Each document has 10 fields. Each field can have any ...
21 views

### Difference between arithmetic vs geometric random walk

I have read about arithmetic and geometric random walks. What is the difference between them?
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### Variance Estimation in case of nonrespondents

I saw in the book of Rubin (1987) that an increase in variance of estimation will occur due to nonresponses. But I wonder the reason behind this. Thanks for your shares!
18 views

### categorizing monthly gross income

what is the best way to categorize or even bin monthly gross income? As of now, the variable for income is numeric and continuous. I have seen many examples for annual income. Should I categorize ...
11 views

### Multi-response GLMM in Jags

I have a data set with 8 response variables (all counts, they are 8 species of mammals). The responses are not independent, and I would like to measure the covariance between them (different ...
15 views

### Distribution for semi open interval

I have an application where I get back the time to perform an operation, the times are in the interval ]0:inf[ and I have this crazy idea. Lets say I know the mean ...
17 views

### How to transform data into discrete-time or time-to-event problem

I have a breast cancer dataset and my goal is to predict a patient's risk per time period using classifiers in WEKA. According to this thread about employment with a similar nature as to my problem, ...
19 views

### Help in Bayesian modeling with WinBUGS [on hold]

I am currently working on my thesis and interested in factor analysis for spatially correlated data using WinBUGS. I wrote the model but when am trying to use it ...
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### R-Cran Imbalanced data Smote problem [migrated]

I am using the following CRAN package DMwR to deal with the problem of imbalanced data : Code is the following: ...
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