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Comparing Means in Spss

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1 Chapter 7 Comparing Means in SPSS (t-Tests)

This section covers procedures for testing the differences between two means using the SPSS Compare Means analyses. Specifically, we demonstrate procedures for running Dependent-Sample (or One-Sample) t-tests, Independent-Sample t-tests, Difference-Sample (or Matched- or Paired-Sample) t-tests. Unfortunately, SPSS does not provide procedures for running Z-tests. For the following examples, we have created a data set based on cartoon 9.1 (Cow Poetry). To obtain our data, we have randomly drawn a sample of 30 cows from the population of cows owned by Farmer Perry. With the measurements we take from this sample we are going to ask three research questions. First, we are interested in the number …show more content…

Running the Analyses In this example we present the steps for using One-Sample T Test... data analysis procedure to determine whether a sample mean is significantly different from a criterion value (in this case the population mean). Before you can run this type of analysis you will need to know the value that you want to

4 compare with your sample mean. In this case our test (comparison) value is 10 and was obtained by finding the average number of times every one of Farmer Perry’s cows touched the electric fence (i.e., the population mean for fence touching). In the procedure presented bellow, we are going to perform two tests at the same time. The first test will compare the mean of fencetch (frequency of touching the electric fence prior to attending cow school) with the population average for touching the electric fence. The second test will compare mean of fenctch2 (frequency of touching the electric fence after attending cow school) with the population average for touching the electric fence. One-Sample T Test Steps (See Figure 9.4): From the Analyze (1) pull down menu, select Compare Means (2), then select One-Sample T Test... (3) from the side menu. In the One-Sample T Test dialogue box, enter the variables fencetch and fenctch2 in the Test Variable(s) field by either double-left-clicking on each variable or selecting the variables and

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