What is a standardized variable?

Answer 1

That would be a variable converted to a convenient measure, usually, to z scores.
To convert to z scores, find the standard deviation and mean of your data set.
Then take each item, subtract the mean, and divide by the standard deviation.
This gives you a standardized data set that you can analyse with the properties of the normal distribution.
For more info see..
http://en.wikipedia.org/wiki/Standardized_coefficient
http://www.microsiris.com/Statistical%20Decision%20Tree/Glossary.htm (scroll about 3/4 of the way down to the definition)
http://davidmlane.com/hyperstat/normal_distribution.html
http://www.stattrek.com/Lesson2/Normal.aspx
http://www.uark.edu/misc/lampinen/tutorials/normal.htm
http://sampson.byu.edu/courses/zscores.html