ch3 - Ch u ong 3 T ONG TH E V ` A M AU 1. T ONG TH E V ` A...

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Unformatted text preview: Ch u ong 3 T ONG TH E V ` A M AU 1. T ONG TH E V ` A M AU 1.1 T ong th e Khi nghi en c uu v ` e mo . t v an d ` e ng u ` oi ta th u ` ong kh ao sat tr en mo . t d au hi e . u n`ao d o, cac d au hi e . u n`ay th e hi e . n tr en nhi ` eu ph ` an t u. Ta . p h o . p cac ph ` an t u mang d au hi e . u d u o . c go . i l`a t ong th e hay d am d ong ( population ). V du . 1 Nghi en c uu ta . p h o . p g`a trong mo . t tra . i ch an nuoi ta quan tam d en d au hi e . u tro . ng l u o . ng. Nghi en c uu ch at l u o . ng ho . c ta . p cua sinh vi en trong mo . t tr u ` ong da . i ho . c ta quan t am d en d au hi e . u di em. Chu y Trong ph ` an n`ay ta s u du . ng mo . t s o khai ni e . m v`a k hi e . u sau: 1. N: s o ph ` an t u c ua t ong th e, d u o . c go . i l`a k ch th u oc c ua t ong th e. 2. X * : d au hi e . u m`a ta kh ao sat. 3. x i ( i = 1 ,k ): gia tri . c ua d au hi e . u X * do d u o . c tr en ph ` an t u c ua t ong th e ( x i l`a thong tin m`a ta quan tam, c`on cac ph ` an t u cua t ong th e l`a va . t mang thong tin). 4. N i ( i = 1 ,k ): t ` an s o c ua x i (s o ph ` an t u co chung gia tri . x i ). 5. p i = N i N : t ` an su at c ua x i . B ang c o c au c ua t ong th e S u . t u ong ung gi ua cac gia tri . x i v`a t ` an su at p i d u o . c bi eu di en b oi b ang c o c au t ong th e theo d au hi e . u X * nh u sau: Gia tri . c ua X * x 1 x 2 ... x k T ` an su at p i p 1 p 2 ... p k 59 60 Ch u ong 3 . T ong th e v` a m au C ac d a . c tr ung cua t ong th e 1. Trung b` nh c ua d au hi e . u X * (trung b` nh c ua t ong th e) m = k X i =1 x i p i . 2. Ph u ong sai c ua d au hi e . u X * (ph u ong sai c ua t ong th e) 2 = k X i =1 ( x i- m ) 2 p i . 3. D o . l e . ch ti eu chu an c ua d au hi e . u X * ( d o . l e . ch ti eu chu an c ua t ong th e) = 2 = v u u t k X i =1 ( x i- m ) 2 p i 1.2 M au T ` u t ong th e l ay ra n ph ` an t u v`a do l u ` ong d au hi e ....
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This note was uploaded on 01/18/2012 for the course INFORMATIK 2011 taught by Professor Phanthuongcang during the Winter '11 term at Cornell University (Engineering School).

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ch3 - Ch u ong 3 T ONG TH E V ` A M AU 1. T ONG TH E V ` A...

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