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


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 2

9.6 t-Test to Compare Two Population Means: Independent Samples (Unequal Variances)

Does alcohol impair your visual/motor skills?  Two randomly selected groups of 20 people were given either alcohol to drink or placebo, and they then had their visual and motor skills tested.  Those who drank alcohol made an average of 4.3 errors with a standard deviation of 2.5 errors.  Those who drank the placebo made an average of 1.7 errors with a standard deviation of 0.7 errors. Use a 0.02 significance level to test the claim that there is a difference between the two groups (Do not assume equal variances).  Does alcohol lead to more mistakes? 

« back