Saturday, June 25, 2011

Math Forum - Ask Dr. Math

Math Forum - Ask Dr. Math

inf means "infimum," or "greatest lower bound."  This is  slightly different from minimum in that the greatest lower bound is  defined as:  x is the infimum of the set S [in symbols, x = inf (S)] iff:  a) x is less than or equal to all elements of S b) there is no other number larger than x which is less than or equal    to all elements of S.  Basically, (a) means that x is a lower bound of S, and (b) means that  x is greater than all other lower bounds of S.

Thursday, June 23, 2011

Data mining Blog, Preprocessing, Normalization

Data mining Blog, Preprocessing, Normalization

Outliers can be found by using a technique called box plot (http://en.wikipedia.org/wiki/Box_plot)

Before we normalize the data set, we need to check for outliers

There are two possible ways to handle outliers in the data
1. Ignore them, remove from the data set (or)
2. Reassign the value to of appropriate upper or lower threshold.