ANOVA Flashcards
(15 cards)
ANOVA stands for
analysis of variance
what is an ANOVA test
significant differences for between group variation versus within group variation
how to calculate degrees of freedom for between group variance
Df = k - 1
Df = between group degree of freedom
k = # of groups
how to calculate degrees of freedom for within group variance
Df =k(n-1)
Df = degrees of freedom
k = number of groups
n = number of patients/data points
F ratio
assess whether between group or within group variation is larger
how are F-Ratios implemented
basically the same as p value (<0.05)
planned comparison
at the outset, comparison planned between specific group
post-hoc comparison
done after preliminary analysis
after F-value turns out to be significant
bonferroni correction
correction of alpha level when comparing two groups after ANOVA shows significance
how to calculate a bonferroni correction
take alpha error / by n
0.05 / number of treatment variables
what is a two-way ANOVA
interaction between two classes of independent variables on dependent variable
ie - are women vs men better after x vs y treatment
what does ANCOVA mean
analysis of co-variance
explain the usage of ANCOVA testing
multiple classes of independent variables in the analysis for effect on dependent variable
explain usage of a repeated ANOVA measure
if you have an experiment with multiple treatment variables (indep) in relation to a single outcome variable (dependent) over the course of time with repeated measurements
what needs to occur often in repeated measures ANOVA
bonferroni correction due to multiple comparisons
