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Course Documents

Chapter 1 - Intro

Chapter 2 - Methods for Describing Sets of Data

Chapter 3 - Probability

Chapter 4 - Discrete Random Variables

Chapter 5 - Normal Random Variables

Chapter 6 - Sampling Distributions

Chapter 7 - Confidence Intervals

Chapter 8 - Tests of Hypothesis: One Sample

Chapter 9 - Confidence Intervals and Hypothesis Tests: Two Samples

Sample Exam I: Chapters 1 & 2

Sample Exam II: Chapters 3 & 4

Sample Exam III: Chapters 5 & 6

Sample Exam IV: Chapters 7 & 8

Ask the Professor Forum

Hi professor
I am confused with the results of #36 on the hw. The confidence interval came out to be 1.21 and 7.54. So the results are that there is a significant difference because they are both positive. However, since both are positive results, doesn't that mean that the first mean is bigger. And according to the problem, the 1st mean is the 1st score before retaking the exam. However, the results show that the students get a better score after retaking the exam (which is the 2nd mean in the problem). Can you please explain the results.

Thank you

Posted to STATS 2 on Tuesday, October 15, 2013   Replies: 2

Professor Mcguckian
11:06 PM EST

Hi Shirley,

The subtaction to get the differences in this problem was done (Second score - First Score), so that is why the positive interval indicates the second scores are higher. 

Hope that clears it up,

Professor McGuckian

11:19 PM EST
Great! Thank you

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