Statistical Sciences 1024A/B Lecture Notes - Lecture 19: List Of Statistical Packages, Two Trees Of Valinor, 2Degrees

• School: Western University
• Department: Statistical Sciences
• Course: Statistical Sciences 1024A/B
• Professor: Lori Murray

Document Summary

We have two independent simple random samples from two populations. Both populations are normally distributed with unknown means and variances. 1 is the mean of the first population. 2 is the mean of the second population. We want to make inferences about 1 and 2 or 1 - 2. Some researchers compared the skull measurements of 84 etruscan males to 70 modern italian males to examine this question. Sample 1 has n1 observations and degrees of freedom n1 1. Sample 2 has n2 observations and degrees of freedom n2 1. The textbook suggests taking the smaller of the n1 1 and n2 -1 as the degrees of freedom. For use only when statistical software is not available. Consequences of using the conservative choice for d. f. Suppose n1 1 is the minimum of n1 -1 and n2 -1. In other words, the conservative choice gives us a smaller value for our degrees of freedom.