Statistics R coding

R code help

Mean absolute deviation.

Tells you how far “on average” the observations are from the mean. It’s very interpretable, but has a few minor issues (not discussed here) that make it less attractive to statisticians than the standard deviation. Used sometimes, but not often.

R

• 4 panels:

  • top-left: scripts and files

  • bottom-left: R console

  • top-right: objects, history and environment

  • bottom-right: tree of folders, graph window, packages, help window, viewer

Ratio Scale 

A ratio scale variable is where zero really means zero, and you can multiply and divide 

Good example = response time (RT)

Variance.

Tells you the average squared deviation from the mean. It’s mathematically elegant, and is probably the “right” way to describe variation around the mean, but it’s completely uninterpretable because it doesn’t use the same units as the data. Almost never used except as a mathematical tool; but it’s buried “under the hood” of a very large number of statistical tools.