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Showing posts from March, 2019

SIMPSON'S PARADOX

        Let us start with an example.  Consider math and biology teachers working in a school.  Every year, they train students and send to school final examinations.  Some students pass.  Some students do not make it.  Every year, each teacher gets 'percentage of passes' score.      The pass percentages for each teacher for two years are given below.                     Math teacher        Biology teacher    Year I           70/80 = 87.5%       20/20 = 100% Year II          10/20 = 50%         50/80 = 62.5% Total             80/100 = 80%       70/100 = 70%     Here, the denominator is the number of students appeared and the numerator is the no.of students passed. ...