Between Subjects Anova Flashcards
when is a between subjects anova used
if they wish to explore between 3 / more independent conditions on a single variable
give an example of this
theory= hair colour associated with working memory compared differences between scores on wm with different hair colours.
what are the variables in this study
between subjects - hair colour
IV- 4 levels (hair colour)
DV - scores on WM test
what does the anova do / not do
tells us if its significant across conditions but not if they are different from each other
what is the purpose of post hoc comparisons
to look at individual contrasts to make comparisons
what are the assumptions of a between subjects anova
normally distributed data
homogeneity of variance / equality of error variances
interval / ratio data (can be ordinal as its a v robust test)
what is homogeneity of variance
within each level of the IV variances in DV should be similar
what test do you use to look at homogeneity of variance
Levene’s test but if its not homogeneity then use Welch’s F
what does looking at means do?
shows effect size = small even though significant results
what graphs do you use for between subject anovas
cluster bar graphs= good for mixed designs
cluster by between subjects
what do error bars show?
the amount of spread around the mean in the data / show confidence intervals simply.
look see that probably statistic significant difference between two means
1 error bar bigger = more variance w/ in the group
what is standard deviation
the mean of data spread around the mean
what is the standard error
level of error (spread) of data from a population mean
rule of thumb= if error bars on 2 separate bars do not over lap then there is a statistically significant difference
