analysis of variance Flashcards
1
Q
why is the use of numerous t-tests to compare 2 groups at a time not recommended?
A
increases chance of type 1 error
does not use best estimate of variance
2
Q
when is ANOVA used
A
to compare interval scale variable between 3 or more independent groups
3
Q
hypothesis tested with ANOVA
A
H0- mean in all populations the same
H1- mean in all pops not the same
4
Q
assumptions in ANOVA if sample size small
A
normally distributed outcome in all groups
std deviation of outcome similar in all groups
5
Q
what is between group variation
A
measures differences between group means
6
Q
what is within group variation
A
measures differences between observations within the dame group
7
Q
how to calculate mean squares/variances
A
sum of squares (SS)/ defrees of freedom (df)
