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    Lesson 5 SPSS Paired Sample T Test

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    Janine Lerum
    The document discusses conducting a paired-samples t-test, which is used to analyze within-subjects or matched-pairs designs where observations are linked. It provides an example comparing problem-solving performance alone vs with others, showing the dataset structure and steps to perform the paired t-test in SPSS. The key outputs are the correlation between paired variables, the t statistic, degrees of freedom, and p-value.

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    Lesson 5 SPSS Paired Sample T Test

    Uploaded by

    Janine Lerum
    28 views4 pages
    The document discusses conducting a paired-samples t-test, which is used to analyze within-subjects or matched-pairs designs where observations are linked. It provides an example comparing problem-solving performance alone vs with others, showing the dataset structure and steps to perform the paired t-test in SPSS. The key outputs are the correlation between paired variables, the t statistic, degrees of freedom, and p-value.

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    Lesson-5-SPSS-Paired-Sample-t-Test

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    The document discusses conducting a paired-samples t-test, which is used to analyze within-subjects or matched-pairs designs where observations are linked. It provides an example comparing problem-solving performance alone vs with others, showing the dataset structure and steps to perform the paired t-test in SPSS. The key outputs are the correlation between paired variables, the t statistic, degrees of freedom, and p-value.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    28 views4 pages

    Lesson 5 SPSS Paired Sample T Test

    Uploaded by

    Janine Lerum
    The document discusses conducting a paired-samples t-test, which is used to analyze within-subjects or matched-pairs designs where observations are linked. It provides an example comparing problem-solving performance alone vs with others, showing the dataset structure and steps to perform the paired t-test in SPSS. The key outputs are the correlation between paired variables, the t statistic, degrees of freedom, and p-value.

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    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    of 4

    Lesson 5: Paired-Samples 

    t Test
    Objectives

    1. Conduct a paired-samples t test.
    2. Interpret the output of the paired-samples t test.

    Overview

    The paired-samples or dependent t test is used for within-subjects or matched-pairs designs in which


    observations in the groups are linked. The linkage could be based on repeated measures, natural
    pairings such as mothers and daughters, or pairings created by the experimenter. In any of these
    cases, the analysis is the same. The dependency between the two observations is taken into account,
    and each set of observations serves as its own control, making this a generally more powerful test
    than the independent-samples t test. Because of the dependency, the degrees of freedom for the
    paired-samples t test are based on the number of pairs rather than the number of observations.

    Example

    Imagine that you conducted an experiment to test the the effects of the presence of others
    (independent variable) on problem-solving performance (dependent variable). Assume further that
    you used a within-subjects design; that is, each participant was tested alone and in the presence of
    others on different days using comparable tasks. Higher scores indicate better problem-solving
    performance. The data appear below:

    Participant Alone Others


    1 12 10
    2 8 6
    3 4 5
    4 6 5
    5 12 10
    6 6 5
    7 11 7
    8 5 3
    9 7 6
    10 12 7
    11 9 8
    12 5 2

    The following figure shows the variable view of the structure of the dataset:
    Figure 5-1 Dataset variable view

    Entering Data for a Within-Subjects Design: Key Point

    When you enter data for a within-subjects design, there must be a separate column for each
    condition. This tells SPSS that the two data points are linked for a given participant. Unlike the
    independent-samples t test where a grouping variable is required, there is no additional grouping
    variable in the paired-samples t  test. The properly configured data are shown in the following
    screenshot of the SPSS Data Editor Data View:

    Figure 5-2 Dataset data view


    Performing the Paired-Samples t test Step-by-Step

    The SPSS data file for this example can be found here. After you have entered or opened the dataset,
    you should follow these steps in order.

    Click on Analyze, Compare Means, and then Paired-Samples T test.

    Figure 5-3 Select Paired-Samples T Test

    In the resulting dialog box, click on the label for Alone and then press <Shift> and click on the label
    for Others. Click on the arrow to move this pair of variables to the Paired Variables window.
    Figure 5-4 Identify paired variables

    Interpreting the Paired-Samples t Test Output

    Click OK and the following output appears in the SPSS Output Viewer Window (see Figure 5-5). Note
    that the correlation between the two observations is reported along with its p level, and that the value
    of t, the degrees of freedom (df), and the p level of the calculated t are reported as well.

    Figure 5-5 Paired-Samples T Test output

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