R en Español


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Puerto Rico Statistics Institute (Instituto de Estadísticas de Puerto Rico) has a nice introductory manual on R, written by Dr. Orville M. Disdier. Check it out at


or get access by visiting


BTW, there is a new version of the site which at the time of writing is still in beta at




Azure Miner


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The Azure miner is available now at


It can help you to find Microsoft Azure public resources, news, and more. Recrawling search result pages allows you to build your own curated collection. Be productive with the Azure miner.

In addition, the news  section includes relevant search, blog, and community channels.

Happy Azure day! 🙂

AWS and AI Miners


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We have two new Minerazzi miners, AWS and AI, available now at

Use this miner to easily find Amazon Web Services public resources, news, and more.

Use this miner to quickly find artificial intelligence resources, tutorials, news, and more.

On a side note, here is a little challenge for you. Can you decipher the following string?

iii teen cell fractal gini

The solution is quite obvious.

On the Nonadditivity of Correlation Coefficients Part 2: Fisher Transformations


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This is Part 2 of a tutorial series on the nonadditivity of correlation coefficients. This time we discuss Fisher r-to-Z and Z-to-r transformations and the risks of arbitrarily implementing these.

Misusing the transformations can have a detrimental impact on significance testing, confidence intervals, reported standard errors of correlations, and meta-analysis.

The tutorial is available at




Simple Linear Regression & Correlation Calculator


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This is a new Minerazzi tool available now at


The tool does simple linear regression and correlation analyses, computing Spearman and Pearson correlation coefficients and other relevant statistics.

The companion default example was intentionally selected to illustrate that for rank data free from ties, Spearman and Pearson correlation coefficients are the same thing.


On the Nonadditivity of Correlation Coefficients Part 1: Pearson and Spearman Coefficients


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This is Part 1 of a tutorial series on the nonadditivity of correlation coefficients. We demonstrate why it is not possible to arithmetically add, subtract, and average Pearson’s r or Spearman’s rs.

The article is available at


07-04-2017 update: In page 1 the line for the Beta1 should read “is the slope of a simple linear regression model”. My fault. Fixed today along with few other nuances.

Enjoy it!

t,p, & Effect Size Estimator


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This is a new Minerazzi tool, available now at


This tool estimates t-scores from p-values and vice versa for a given number of degrees of freedom υ. Just enter a (t,υ) or (p,υ) pair and this tool will solve for the missing term.

The tool also estimates the statistics that one would obtain if the computed estimates correspond to a set of paired variables (x, y), or to effect sizes from any two samples of same sizes (n1 and n2); i.e. samples with same degrees of freedom (υ1 and υ2).

The tool’s page lists some interesting exercises and good references for effect size conversions and meta-analysis in general. Enjoy it!