One-way ANOVA Flashcards
When would you use a one-way analysis of variance (ANOVA)?
When you wish to determine if there are any statistically significant differences between the means of two or more independent groups.
e.g. whether exam performance differed based on test anxiety levels amongst students (i.e. DV = exam performance, IV = test anxiety level).
What is a one-way ANOVA also referred as?
A between-subjects ANOVA, or one-factor ANOVA.
If the one-way ANOVA has an IV with only two groups, which statistical test is better suited?
An independent-samples t-test.
Why is a one-way ANOVA an omnibus test statistic?
Because it can only tell you that at least two groups were different; it cannot tell you which specific groups were significantly different from each other. To determine which groups are different, you must use follow-up tests.
What follow-up tests can determine which groups are significantly different from each other?
Either a post hoc test or custom contrasts.
How many DV’s are needed to run a one-way ANOVA?
Only one DV can be used.
What level must the DV be measured at?
The continuous level (e.g. height, age, salary, IQ).
How many IV’s are needed to run a one-way ANOVA?
Only one IV can be used, that consists of two or more categorical, independent groups. Typically, a one-way ANOVA is used when you have three or more groups. An independent-samples t-test is more commonly used for one IV with only two groups.
Give an example of an IV with three categorical, independent groups.
Example 1: Ethnicity (Caucasian, African American, and Hispanic).
Example 2: Physical Activity (Low, moderate, high).
If you have two IV’s, which statistical test would be better suited?
A two-way ANOVA.
What term is best to describe the “groups” of the IV?
‘Categories’ is the correct term. ‘Levels’ should be used instead when groups have an order (e.g. fitness level, ‘low, moderate, high’.
Define independence of observations, and how to achieve this in the one-way ANOVA.
When there is no relationship between the participants in any of the groups being used. This includes participants between groups being related (e.g. husband and wife), and participants in one group being able to influence other participants in another group. Researchers usually achieve independence of observations by having different participants in each group.
If your study doesn’t have independence of observations, what statistical test is more appropriate to use?
A one-way repeated measures ANOVA.
Can a one-way ANOVA be used if there are any significant outliers in the groups?
No.
Can a one-way ANOVA be used if the DV isn’t approximately normally distributed for each group of the IV?
No.
