Enjoy learning Statistics Online! Please be sure to share and subscribe to our YouTube channel.

ASK THE PROFESSOR FORUM

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

Example 110

Example 110:  In a 2011 report by the CDF (Children’s Defense Fund), it was reported that a random sample of 29 black males with only a high school degree earned on average $25,418.  The standard deviation is estimated to be $5,500.  Use the sample data and a 95% confidence level to find the margin of error E and the confidence interval for µ.  A 95% confidence interval was constructed for white males, and it was found that the true mean income for white males with only a high school degree was between $33,215 and 37,399.  Comparing these two intervals, can we conclude there is a significant difference between incomes for the two groups? 

« back