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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

Problem 1

9.5 t-Interval to Compare Two Population Means: Independent Samples (Unequal Variances)

A researcher wants to know if statisticians in the private sector are paid better than statisticians in the public sector.  She selects random samples from both areas the results are summarized below.  Form a 95% confidence interval for the average difference between the salaries of government statisticians and private sector statisticians (Do not assume equal variances).

 Government                        Private

n = 26                                    n = 28
sample mean = 35.50           sample mean = 54.60
s = 4.16                                 s = 4.4

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