Review of Median Example 1: Find the median of the data set {3, 7, 8, 5, 12, 14, 21, 13, 18}

23.5.2012

Answer: 2019+(71-0.5)/(365+0)=2019.193;
2013+(97-0.5)/(365+0)=2013.264;
2012+(143-0.5)/(365+1)=2012.390;

Discretization

I	D	D_d
100	2000.000	D1
101	2003.120	D1
102	2011.144	D3
103	2005.333	D2
104	2001.108	D1
105	2013.975	D3
106	2020.000	D4
107	2017.455	D4
108	2012.143	D3
109	2018.555	D4
110	2007.005	D2

Answer:
To discretize the D attribute into 4 bins(consecutive intervals), we use this formula
here, is the number of bins, are min and max gradations of the attribute. So ;
_s; ;
;
now we put D attribute elements into bins, if it is in the first interval we put D_d column D1…

Bins	D_d
[2000.000 , 2005.000]	D1
(2005.000 , 2010.000]	D2
(2010.000 , 2015.000]	D3
(2015.000 , 2020.000]	D4