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The Standard Normal Distribution in R

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Updated:  
2017-07-05 16:57:46
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Statistical Analysis with R Essentials For Dummies
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Working with the standard normal distribution in R couldn’t be easier. The only change you make to the four norm functions is to not specify a mean and a standard deviation — the defaults are 0 and 1.

Here are some examples:

> dnorm(0) [1] 0.3989423 > pnorm(0) [1] 0.5 > qnorm(c(.25,.50,.75)) [1] -0.6744898 0.0000000 0.6744898 > rnorm(5) [1] -0.4280188 -0.9085506 0.6746574 1.0728058 -1.2646055 This also applies to the tigerstats functions:

> pnormGC(c(-1,0),region="between") [1] 0.3413447

> qnormGC(.50, region = "below") [1] 0

To standardize a set of scores so that you can compare them to other sets of scores, you convert each one to a z-score. The formula for converting a score to a z-score (also known as a standard score) is eq08002.

About This Article

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About the book author:

Joseph Schmuller, PhD, is a cognitive scientist and statistical analyst. He creates online learning tools and writes books on the technology of data science. His books include R All-in-One For Dummies and R Projects For Dummies.