Stat 211 Handout 9 (Chapter 9): Inferences Based on Two Samples tests

1. 
   One-sided (One tailed) test:
   

1. 
   Lower tailed: H₀: population characteristics  claimed constant value
   

2. 
   Upper tailed: H₀: population characteristics  claimed constant value
   

2. 
   Two-sided (Two tailed) test: H₀: population characteristics = claimed constant value
   

1. 
   Independent Samples
   

1. 
   Population characteristics: Difference between two population means, ₁-₂.
   

m and n are the sample sizes for X's and Y's, respectively.