Assignment: Two Independent Samples

 

The purpose of this activity is to give you guided practice in obtaining and interpreting a 95% confidence interval for μ1 − μ2 following a two-sample T-test that rejected H0. Recall our second example:

Our variable Age Group (X) has two categories: males 20–29 years old and males 75+ years old. These two groups form our two populations. For each population we have a separate μ, representing the weight (Y) mean of that population. For each population we take an SRS. From population 1 of males 20–29 years old, we obtain an SRS of size 712, and find that it has a mean of 83.4 and SD of 18.7. From population 2 of males 75+ years old, we take an SRS of size 1001 and find that it has a mean of 78.5 and SD of 19.0. 

Instructions

Click on the link corresponding to your statistical package to see instructions for completing the activity, and then answer the questions below.

R | StatCrunch | Minitab | Excel 2007 | TI Calculator

Question:

Obtain the 95% confidence interval for μ1 – μ2 and interpret it in context.