Archive:Advanced ANOVA/One-way ANOVA: Difference between revisions
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This tutorial | This tutorial teaches understanding and use of '''one-way ANOVA''' as a statistical technique for testing mean differences between three or more independent groups. Practical exercises are based on using [[SPSS]]. | ||
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Revision as of 03:07, 18 August 2008
Template:50%done This tutorial teaches understanding and use of one-way ANOVA as a statistical technique for testing mean differences between three or more independent groups. Practical exercises are based on using SPSS. |
Introduction
- Unit outline (updated - to upload/link)
- [[../Assessment/]]
General steps
- Establish hypothesis/hypotheses
- Make these as explicit and clear as possible
- Break complicated hypotheses down into sub-hypotheses
- Each hypothesis should be able to be answered as "yes" or "no"
- It should be clear from the hypotheses what the predicted relation is between an IV and a DV
- Identify IV (categorical; between-subjects) and DV (at least interval)
- Examine assumptions:
- The data in each cell is normally distributed
- Homogeneity of variance (the variance in each cell is similar)
- Cells are independent
- Examine descriptive statistics, particularly the four moments (M, SD, Skewness, Kurtosis) overall, and also for each group
- Examine graphs, e.g.,:
- Histograms
- Normal probability plot
- Error-bar graph
- Conduct inferential test (ANOVA) and interpret significance of F
- Conduct follow-up tests (planned contrasts or post-hoc tests) if F is significant
- Calculate and interpret effect sizes
- Eta-square (omnibus - equivalent to R2)
- Standardised mean effect size (difference b/w two means)
Visual ANOVA
- Understanding ANOVA Visually (may require viewing with Internet Explorer)
- Under what conditions would F be the smallest?
- Under what conditions would F be the largest?
- Now explore the same ideas with this more advanced Visualisation Tool for One-way and Two-way ANOVA Applet
Error bar graphs
- Use any dataset
- Conduct a one-way ANOVA and graphically present the means and confidence intervals using an Error Bar Graph - is this error bar chart consistent with the statistical results? Why? Why not?
Data
See also
- Analysis of variance/Data analysis tutorial (3rd year tutorial)
- Analysis of variance (Wikipedia)
External links
- ANOVA (ucspace)