ANOVA: Analysis of Variance
An inferential parametric statistic we use for comparing the means of a few groups (F for a few– 3 or more)
Between Groups ANOVA
An inferential parametric statistic we use for comparing the means of three or more groups and each group is composed of different participants.
-AKA Independent groups ANOVA or a Simple ANOVA
What is Between Groups?
- Comes up a lot in connection with ANOVA.
- The source table has a sum of squares (SS) and mean square (MS or variance) associated with the between groups line. This reflects the effects of the IV plus error variance.
- IMPORTANT: We are always comparing differences between groups produced by the IV against differences due to change.
What is a confounding variable?
A variable that systematically covaries with the IV so we can’t determine which variable is at work on the DV = confound.
What is counterbalance?
Effort to minimize order effects by varying the order of presentation of different levels of the IV from one participant to the next.
- If there are 3 different levels of the IC, there are THREE different orders and we would need 6 participants, one for each order
When is counterbalancing used?
In repeated measures designs to eliminate order effects.
What is eta-squared?
- A measure effect of Cohen’s d.
- Tells us how much variability in the DV is explained or accounted for by the IV.
What is the effect size?
The proportion of variance in the DV that is explained by the IV.
- Cohen’s d or eta-squared
What is error?
- mistake
- everything that’s unaccounted for in our research
What type of errors are there?
- sampling error
- error variance
- systematic error called confounds
- random
What is factor?
A term used for IV in a study with more than one IV.
What is F-ratio?
The formula for the F test is the ratio of between-groups variance to within-groups variance.
I can also be expressed as the ratio of treatment variance to error variance.
T/F: If the IV is having no effect on the DV, the F ratio will be f = 1?
True
T/F: If the IV is having an effect on the DV, the F ratio will be significantly greater than 1?
True
What is level?
A discrete value or condition that an IV can take on.
Mostly in ANOVA
What is an LSD test?
Inferential stat for making pair-wise comparisons between any two means in an analysis of variance.
What is one-way ANOVA?
Inferential stat test for comparing the means of a few groups (3 or more)
- using independent groups or between subjects design.
What are one-way repeated measures ANOVA?
Stat test for comparingg the means of a few (3 or more) groups using a repeated measures, or correlated-groups, or within-subjects design.
- tested on all-levels of IV
What is order effect?
Effect produced when a participant’s behavior changes when the DV is measured repeatedly.
What is the Post hoc test?
“After the event”
ANOVE: we can follow it by testing all possible pairs of groups to pinpoint which ones differ significantly from each other and which ones of not.
WE WILL ONLY USE LSD TEST
What is Prep?
Measure of likelihood we can replicate the results of a study.
What is repeated measures?
Research in which one group of people is measured repeatedly or is in each condition of the study.
AKA Within-Subjects Factor
- One-Way ANOVA
What is a sampling error?
Amount of inaccuracy in data due to studying a sample rather than testing the entire population.
KNOW HOW TO CALCULATE ELEMENTS ON THE SOURCE TABLE!!!
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