Module 11: Single Factor ANOVA

Question 1

F test use

Answer 1

-evaluate difference in variance in 2 groups

Question 2

F test ratio of variances (f score)

Answer 2

-Fo: s2a / s2b
-s2a is for variance in first group
-s2b is for variance in second group

Question 3

F test null and alternative

Answer 3

-Ho: F =1
-Ha: F =/ 1

Question 4

F test null distribution shape

Answer 4

• f distribution
  -looks more like a chi squared test

Question 5

F test degrees of freedom

Answer 5

-dfa: na - 1
-dfb: nb -1
-na is for number of sampling units in group a
-nb is for number of sampling units in group b

Question 6

F test reporting

Answer 6

-mean, SD, and sample size for each group
-observed f score (2 decimal places)
-degrees of freedom
-p value

Question 7

Single factor anova use

Answer 7

-one numerical and one categorical variable

Question 8

Sources of variation for ANOVA

Answer 8

-residual variation: variation among sample units within a categorical level
-group variation: variation among categorical levels

Question 9

ANOVA f score

Answer 9

-compares residual variation to group variation
-F0= group variation / residual variation

Question 10

ANOVA null and alternative

Answer 10

-statement of means: written first
-Ho: u1 = u2 …
-Ha: u1 =/ u2 …

-f test written second
-Ho: f <= 1
-Ha: f > 1

Question 11

F score null distribution shape

Answer 11

• f distribution

Question 12

ANOVA degrees of freedom

Answer 12

-dfg: k - 1
-dfe: n - k
-k is for number of levels in categorical variable
-n is for total sampling units

Question 13

ANOVA reporting

Answer 13

-mean, SD, and sample size for each group
-observed F score
-degrees of freedom
-p value

Question 14

TukeyHSD test

Answer 14

-compares means of all possible differences