Class Meeting 18

# Class Meeting 18 - CHEN 3010 Applied Data Analysis Class...

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CHEN 3010 Applied Data Analysis Class Meeting # 18 Thursday, Oct. 28 Today’s Topics Paired t-test F test (ratio of variances) Reading for next Tuesday: pages 235-245 HW# 8 Posted on the web site, due Thursday, Nov 4th

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The Paired t-test Definition: A special case of a t-test for comparing 2 means when measurements are taken in pairs Consider a clinical study comparing skin sensitivity to two Case 1: Two groups of subjects. One group receives cream A, and the other cream B Case 2: One group of students, Each person in the group receives both creams Which case is a paired t-test, and which is an unpaired comparison? Case 1 is an unpaired comparison Case 2 is a paired comparison and allows the paired t-test
Paired t-test Hypothesis Testing Null Hypothesis: H O : μ A - μ B =0 H 1 : μ A - μ B >0 Reject H O if t O > t α, n-1 H 1 : μ A - μ B <0 Reject H O if t O < t α, n-1 H 1 : μ A - μ B ≠0 Reject H O if t O > t α/2, n-1 or if t O < t α/2, n-1 n S d d o t / = d = average of the differences S d = standard deviation of the differences

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Paired t-test Hypothesis Testing Patient A (cm) B (cm) 1 2 3 4 5 6 7 8 9 10 1.2 0.8 0.3
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## This note was uploaded on 10/11/2011 for the course CHEN 3010 taught by Professor Kompala,dh during the Spring '08 term at Colorado.

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Class Meeting 18 - CHEN 3010 Applied Data Analysis Class...

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