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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

9.3 t-Interval to Compare Two Population Means: Independent Samples (Equal Variances)

Who gives a higher real estate assessment? In an experiment, a single home was assessed by a both real estate appraisers and local government tax assessors. A randomly selected sample of 22 appraisals done by the real estate appraisers had an average value (in thousands) of $212.1 with a standard deviation of $8.48. A randomly selected sample of 23 appraisals done by tax assessors had an average $225.3 with a standard deviation of $9.01. Find the 90% confidence interval for the true mean difference between the two types of appraisals (Assume equal variances). Is there a significant difference?