1 / 7

2-Way ANOVA

2-Way ANOVA. Learning Objectives. Compute 2-Way ANOVA by hand Calculate sums of squares for main effects and interaction Complete ANOVA source table Correctly interpret results Compute 2-Way ANOVA using SPSS Correctly interpret output. ANOVA Partitions Variance.

florida
Download Presentation

2-Way ANOVA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 2-Way ANOVA

  2. Learning Objectives • Compute 2-Way ANOVA by hand • Calculate sums of squares for main effects and interaction • Complete ANOVA source table • Correctly interpret results • Compute 2-Way ANOVA using SPSS • Correctly interpret output

  3. ANOVA Partitions Variance • Total variance is divided into • Within groups – individual differences, nuisance variance, error • Between groups – treatment effects & random error • With 2-Way ANOVA, you have 2 IVs instead of 1. Variance between groups is partitioned into 2 Main Effects and an Interaction.

  4. ANOVA Significance Test • ANOVA with 1 IV has 1 F test • ANOVA with multiple IVs has multiple F tests, one for each Main Effect and one for each Interaction. • With 2-Way ANOVA, there are two main effects and 1 interaction, so there are 3 F tests. All, some, or none may be significant. Critical values change depending on df for denominator.

  5. Example 1: 2 kinds of Therapies • Treatment of panic attacks. • IV1: psychotherapy. 3 levels: conventional, experimental, and control (wait list). • IV2: Anti-anxiety drug. 2 levels: drug vs. control. • DV is number of panic attacks during 1 week after 6 wks therapy. • See handout for data. Work thru example.

  6. Example 2: Types of training • Military electronic troubleshooters fix radar, missile guidance systems, etc. • Standard training is experience with common problems. • New training. • on top of standard training. • IV1: Theory of electronics (new module). • IV2: Practice of troubleshooting (new module). • Work thru handout.

  7. SPSS • Download file. • Run SPSS & match to hand computations. • Produce a graph of the cell means.

More Related