T-Test and Anova Essay

2102 Words May 6th, 2014 9 Pages
BUS 310
Notes regarding Two-Sample t-Tests and ANOVAs

In Chapter 9, we learned how to conduct a t test of a hypothesis when we were testing the mean of a single sample group against some pre-determined value (i.e., the 21.6 gallons of milk consumption as the national average). This week, in Chapter 10, we will see how to test hypotheses that involve more than one sample group—such as testing to see if males are significantly taller than females. If we have two groups, then the technique that we will use will still be a t test. If we have more than two groups, then we will have to use a different test called Analysis of Variance (ANOVA, for short).

The good news is that the decision rules for hypothesis testing that we learned
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If you click on Data Analysis and then scroll down to the t-test options (they are in alphabetical order), you will see that there are three different types of t tests that Excel can perform. For purposes of this course, we will not be using the t-Test: Two Sample Assuming Unequal Variances, so you will not need to worry about that one. We will use t-Test: Two Sample Assuming Equal Variances whenever we have two completely separate groups (i.e., males and females, college students and high school students, etc.) for which we have data. We will use t-Test: Paired Two Sample for Means (a paired sample t test) whenever we have one group of subjects for which we have two separate observations, such as a before and after test for a weight loss program—it would be the same participants and we would measure their weight twice, once before the program and again after the program.
Let’s consider the example data at the top of page 432. A company is considering adopting a new software system, but they want to make sure that it will work more quickly than their current system. A sample was set up where the current software was used and the time taken to complete the project was measured for one group and then for a second group, the new software was used and the time taken to complete the project was measured. This is going to be a t-Test: Two Sample Assuming Equal Variances because we have two

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