What are four inferential statistical tests?
What does correlation measure?
Are two variables related
What does simple regression predict?
Predicts one (continuous) variable from another (continuous) variable
What are two types of chi-square?
2. test of independence (two categorical variables)
What are the three types of t-tests
What does a confidence intervals show?
The range of plausible values for the parameter
What is shown in a between groups confidence interval?
If the CIs overlap <25% difference, then it is statistically significant
What is shown in a within-groups confidence interval?
If CIs do not overlap then the difference is statistically significant
If CIs overlap, statistical significance cannot be inferred
What does a confidence interval show in relation to effect size?
The magnitude of effect in standardised units
-emphasis on the data, not statistical significance
When are t-tests used?
When we are interested in whether the means of two populations differ
What is done if there are multiple means to compare?
-could choose multiple t-tests
What is a problem with conducting multiple t-tests (2)?
- each test has a .05 probability of a type 1 error, so making many tests increases type 1 error rate
What is analysis of variance (ANOVA) used for?
Testing hypotheses involving multiple means in a single test
What is the simplest ANOVA test of variance?
One-way Anova
-One IV (factor) with two or more levels
What type of test is a one-way ANOVA?
It is an omnibus test.
What does the null hypothesis tell us in a one way anova?
That all means are equal.
In a one-way ANOVA, what does rejecting the null hypothesis mean?
Deciding that some means differ. A statistically significant result is ambiguous.
What is total variance in terms of a one-way ANOVA?
Variance of all scores around the grand mean.
What does between-groups variance mean in a one way ANOVA?
Variance is due to the independent variable.
What does a variance in a within-groups (error) design mean?
Variance that is unaccounted for.
What are the three types of variance that ANOVA partitions into?
How do you total the whole variance of data in an ANOVA?
total=between groups + within groups
Who is the statistic from ANOVA “F” named after?
Sir Ronald Fisher
In a one way ANOVA, what assumption is made about independence?
For a between-group Anova, each participant only contributes one score.