Re: "data is skewed" - what does it mean ?

From: Mark Richard <mrichard_at_transurban.com.au>
Date: Fri, 25 Jul 2003 17:13:47 +1000
Message-Id: <26007.339518@fatcity.com>

It's not this simple...

Let's take your low cardinality example... Gender is a good example since there are only two (common) genders - male and female.

A table with 10,000 staff would make the gender column low cardinaility - only 2 distinct values. If you had 5,000 males and 5,000 females then the data would be evenly distributed and therefore not skewed. If, however, you had 9,500 females and 500 males then you have skewed data.

Hopefully this gives some idea of the difference between cardinality and skewed data.

                                                                                                                                      
                      orababy                                                                                                         
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                      ml-errors_at_fatcity                                                                                               
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                      25/07/2003 17:34                                                                                                
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Gogala,

If cardinality is high, then data is evenly distributed.

If cardinality is low, then data is not evenly distributed and hence skewed.

Is my understanding correct...atleast to some extent ?!

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Received on Fri Jul 25 2003 - 02:13:47 CDT