# All Questions

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### Statistical measure of international diversity

I've got a large collection of geotagged tweets, each linking to an article from a given author. For each author, I'd like to derive a number that describes how diverse is their list of tweeting ...
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### Data Science: self study

I need your suggestion to solve this problem: Given a Data Warehouse with e.g. 10 million entries, additional 1000 entries arrive each day. Rather than recomputing the desired aggregates, an ...
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### Shape uncertainty of a 3D point cloud

Given a point cloud of a 3D object, how to calculate the shape uncertainty in this discrete sample set? and what factors maximize or minimize this uncertainty?
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### Grouping similar plots together in a Stripchart [migrated]

I have groups of data that I want to put more closely together on my strip charts ...
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### When compare a variable in different times, one has normal distribution, another doesn't, which test should I use?

The question is to compare means of sales volume in different periods. So I got sales period 1 and sales period 2. Sample size is 40. The skewness, kurtosis, test of normality and histogram all show ...
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### revert minmax normalization back to original value

i'm training a neural network. Normalization of inputs and outputs (training data) are carried out using min Max to a scale of [0-1]. I'm applying backpropagation learning algorithm. Firstly, i need ...
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### Cannot perform tests for multivariate normality. Is my data set too large?

I'm examining the performance of quadratic and linear discriminant models at classification. My dataset has 250,000 observations, 2 groups and 30 explanatory variables. I thought it would be worth ...
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### Incremental Aggregation: need some clarification

I have started some self study on Data mining algorithm. Recently I came accross a problem. I need your hint: Given a Data Warehouse with e.g. 10 million entries, additional 1000 entries arrive each ...
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### Statistical Significance of Turnaround Time

My laboratory recently implemented MALDI-TOF MS for identification of gram negative rods in blood cultures. I collected data retrospectively from laboratory reports comparing the time from isolation ...
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### What is divergence in indicators/oscillators?

What is the direct cause of divergence in indicators/oscillators? Is it because of using the close price? How could I filter it out or isolate it? This would be useful to extract for a predictive ...
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### Reporting sensitivity/specificity using a random process?

I'm using a method that involves cross-validation to make predictions on my dataset. As it splits the data randomly, I will end up with different results (I believe this is an example of a stochastic ...
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### Distribution of a binary matrix times a Bernoulli vector

Suppose we have the vector $\mathbf{Y} = (Y_{1},\ldots,Y_{n})$ where $Y_{i} \sim \textrm{Bernoulli}(p_{i})$ independently. For the applications I have in mind, $n$ will typically be several thousand, ...
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### Is there a SAS equivalent for JMP's life distribution?

I have a work flow where I use SAS to pull and prepare my data into censored data, and then open the SAS dataset in JMP and perform a life distribution analysis on the data. More often than not I use ...
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### What statistical analysis did they do in this paper?

This is really a beginner question. I have to perform a statistical analysis which is exactly the same as the one conducted in the table shown in the picture. Specifically, how to calcolate the ...