Microsoft Office Tutorials and References
In Depth Information
5.1 The 9 STEPS for Hypothesis-Testing
Using the Two-Group t-Test
Objective: To learn the 9 steps of hypothesis-testing using two groups of
people, plants, or animals and the two-group t-test
You will see that these steps parallel the steps used in the previous chapter that
dealt with the one-group t-test, but there are some important differences between
the steps that you need to understand clearly before we dive into the formulas for
the two-group t-test.
5.1.1 STEP 1: Name One Group, Group 1, and the Other Group,
The formulas used in this chapter will use the numbers 1 and 2 to distinguish
between the two groups. If you deﬁne which group is Group 1 and which group is
Group 2, you can use these numbers in your computations without having to write
out the names of the groups.
For example, if you are testing the perceived effectiveness of two different types of
pain medications on college freshmen males, you could call the groups: ‘‘Ibuprofen’’
and ‘‘Acetaminophen,’’ but this would require your writing out the words ‘‘Ibupro-
fen’’ and ‘‘Acetaminophen’’ whenever you wanted to refer to one of these groups.
If you call the Ibuprofen group, Group 1, and the Acetaminophen group, Group 2,
this makes it much easier to refer to the groups because it saves you writing time.
As a second example, you could be comparing ﬂower preference for one type of
hummingbird. Two types of ﬂowers, fuschias and mandevillas, have a vibrant red
color that is a typical attractant found in hummingbird gardens. If you had to write
out the names of the two ﬂowers whenever you wanted to refer to them, it would
take you more time than it would if, instead, you named one ﬂower, Group 1, and
the other ﬂower, Group 2.
Note, also, that it is completely arbitrary which group you call Group 1, and
which Group you call Group 2. You will achieve the same result and the same
conclusion from the formulas however you decide to deﬁne these two groups.
5.1.2 STEP 2: Create a Table that Summarizes the Sample Size,
Mean Score, and Standard Deviation of Each Group
This step makes it easier for you to make sure that you are using the correct numbers
in the formulas for the two-group t-test. If you get the numbers ‘‘mixed-up,’’ your
entire formula work will be incorrect and you will botch the problem terribly.
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