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Repeated Measures ANOVA patterns over time

Repeated Measures ANOVA patterns over time. Case Study. One-Way Repeated Measures. One-way Repeated Measures Designs are used when: the same subjects are measured on 3 or more occasions the same subjects are exposed to 3 or more treatments

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Repeated Measures ANOVA patterns over time

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  1. Repeated Measures ANOVA patterns over time

  2. Case Study

  3. One-Way Repeated Measures • One-way Repeated Measures Designs are used when: • the same subjects are measured on 3 or more occasions • the same subjects are exposed to 3 or more treatments • the same subjects provide three or more ratings that are measured on the same scale • the same subjects receive 3 or more doses of the treatment

  4. Examples • The same subjects are assessed on pre, mid, and post treatment occasions. • The same subjects are given three different types of medication. • The same subjects rate three different aspects of school climate.

  5. Examples

  6. Examples

  7. One-Way Repeated Measures • This design is analogous to the One-way ANOVA we studied earlier in the semester. • One-Way ANOVA designs have a single Between-Subjects IV. • One-Way Repeated Measures designs have a single Within-Subjects IV.

  8. One-Way Repeated Measures • Just like the One-way ANOVA procedure is an extension of the Independent t-test, the One-Way Repeated Measures procedure is an extension of the dependent t-test.

  9. One-Way Repeated Measures • Data from each subject occurs in multiple cells in the design. • In Between-Subjects designs, data from each subject occurs in only one cell in the design.

  10. One-Way Repeated Measures • Just like the One-Way ANOVA procedure, a statistically significant overall F test only tells you that there is difference somewhere among the means. • Post hoc comparisons are needed to detect where the difference(s) lie.

  11. Special Considerations • Additional potential threats to the validity of this type of design: • practice effects • order effects • fatigue effects • carry-over effects • ceiling and floor effects

  12. Assumptions • If you take the univariate approach to Repeated Measures designs, you have a new assumption: • Sphericity (replaces homogeneity of variance) • Consistent pattern to the variances and correlations

  13. Assumptions • If you take the multivariate approach to Repeated Measures designs, you do not have the Sphericity assumption. • Homogeneity of variance-covariance matrices becomes important when there are multiple groups.

  14. Assignments • For Assignment 7, focus on completing an analysis and write-up for one Oneway ANOVA with Repeated Measures.

  15. Our Research Design

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