# Blog Archives

## Unknown Variance Two-Tailed Test of Population Mean

February 11, 2013
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Question The mean safety audit score of ACME Co. stores in New York (n=200) was 74.3pts February last year.  Suppose we decided to sample 22 out of the 200 stores one year later. We find that the sample mean is 78.6pts and the sample standard deviation is 3.2pts.  Can we reject the null hypothesis that

## The Unravelling of Structured Investment Vehicles or Birthdays

January 2, 2013
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The best way for me to achieve deep understanding of a theorem is not through lengthy proofs alone, but through practical application/implementation or as they said in the Marine Corps Pract-App. One of the many reasons I love R is the ease to write functions and test results. The 2008 financial crisis was the topic of a recent dinner

## Correlation: Easy as 1-2-3?

November 1, 2012
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I recently had a task to take a look at some assessment (audit) data. I was assuming, rather hoping for data with a normal distribution and thought it would be a quick case of Pearson correlation between two columns: "Duration" and "Score". Just conjecture at this point as I did not understand what the assessment process

## Tidbit: Correlation and Simple Linear Regression

October 19, 2012
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In business "Correlation" is generically used as a mutual relationship or connection between two or more things; statistically speaking correlation is the interdependence of variable quantities. I overhear many end users request information on the correlation of variables for prediction use, what they are referring to is actually simple linear regression. I don't mean to outline all