ANOVA- Analysis of Variance

What are some tests that can be run after running an ANOVA test?

• Levene’s test: Checks whether two or more groups have equal variances, verifying the homogeneity of data

What is the importance of F value?

• Statistical test that compares variation between groups with variation within groups; larger value suggests that group differences are less likely to occur by chance

What is the importance of F ratio?

• Ratio of the two mean square values, so if the F value is close to 1 then there is no difference between the groups.

• A large F raio means that the variation among group means is more than you’d expect to see by chance.

What is required before running an ANOVA test?

• ANOVA should be used when there are more than two populations being investigated

• Data should be continuos

• Data should be derived randomly and the significances are determined by the difference between the means and variance around the means

What does a large or small p value mean?

Large P Value

• means that the observed differences could easily occur by random sampling

• not the same as saying that the true means are the same, you just don’t have compelling evidence that they differ

Small P Value

• means that you can reject the null hypothesis and that there is statistical difference between the groups

What are some examples of a post-hoc test?

• Tukeys- compares every mean with every mean

• Bonferroni- compares every mean to the control mean

What is a degree of freedom?

• Independent value that can differ without influencing its constraints