Chapter 10 Problem3

# Chapter 10 Problem3 - 29 991 22 8 03 65 03 65 1 50 2 1 1 =...

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QAS129:001 Instructor: Dr. Yudan Zheng 1. To test the effectiveness of a business school preparation course in improving exam scores, 8 students took a general business test before and after the course. The results are given below. Exam Score Exam Score Student Before Course (1) After Course (2) 1 530 670 2 690 770 3 910 1,000 4 700 710 5 450 550 6 820 870 7 820 770 8 630 610 (1) What are the hypotheses tested by the business school? Ho: ud <= 0 H1: ud > 0 (2) Which test would likely be most appropriate to employ? a. Paired t test b. Pooled-variance t test for the difference between two means c. Independent samples Z test for the difference between two means d. Related samples Z test for the mean difference ANSWER: a (3) What is the number of degrees of freedom? ANSWER: 7 (4) What is the value of the standard error of the difference scores? ANSWER:

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Unformatted text preview: ( 29 991 . 22 8 03 . 65 03 . 65 1 50 2 1 1 = = =--= = = ∑ ∑ = = n S n D D S n D D D n i i D n i i QAS128:001 Instructor: Yudan Zheng Sd/ racine n =22.991 (5) What is the test statistic? 17 . 2 991 . 22 50 =-=-= n S D t D D μ T=(/D – ud ) / Sd/racine n (6) What is the critical value for testing at the 5% level of significance whether the business school preparation course is effective in improving exam scores? ANSWER: It is an upper-tail test, therefore, Critical value=tinv(2*alpha,n-1)=tinv(2*0.05,7)=1.895 (7) At the 0.05 level of significance, what is the conclusion for this hypothesis test? ANSWER: Reject the null hypothesis. That is, there is sufficient evidence that the preparation course does improve exam score. 2...
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## This note was uploaded on 12/10/2010 for the course STAT QAS 129 taught by Professor Zheng during the Fall '10 term at Long Island U..

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Chapter 10 Problem3 - 29 991 22 8 03 65 03 65 1 50 2 1 1 =...

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