Session 3a

Question 1

Independent Variable terminology

Answer 1

X or IV

Question 2

Independent Variable (X or IV)
Also called what

Answer 2

a factor or a treatment variable

Question 3

Independent Variable (X or IV) have multiple what

Answer 3

levels

Question 4

what are levels in IV

Answer 4

Levels (treatments) = different values or categories of the independent variable/factor

Question 5

Single-factor (one-way) designs

Involve what

Answer 5

a single IV with two or more levels

Question 6

Single-factor (one-way) designs have what 2 subcategories

Answer 6

One-way independent-groups design (one way ANOVA) which is the point of this lecture
One-way design with repeated measures

Question 7

what are Factorial designs

Answer 7

Involve more than one independent variable with two or more levels

Question 8

Example: two-way independent-groups designs

what is this an example of

Answer 8

factorial design

Question 9

When an experimental design has two factors with two levels each, it is called what

Answer 9

a 2 × 2 factorial design

Question 10

If two factors, one factor has 2 levels and the other factor has how many levels

Answer 10

3 levels, 2×3

Question 11

Purpose of one way ANOVA

Answer 11

To test whether the means of k (≥ 2) populations significantly differ

k is the number of groups

Question 12

Prior requirements/assumptions of one way ANOVA

Answer 12

The population distribution of the DV is normal within each group The variance of the population distributions are equal for each group (homogeneity of variance assumption)
Independence of observations

Question 13

If H0 is true what is the distribution like

Answer 13

normal, all groups are the exact same

Question 14

If H0 is NOT true, there are several possibilities: what could the distribution be like

Answer 14

2 of the distributions are the same and one is not, all of the distribution s are different, etc

Question 15

Why not just test all possibile differences with t-tests? instead of doing one way ANOVA

Answer 15

This would lead to an inflated experiment-wise Type I error rate
The chances of at least one significant difference are > α

Question 16

ANOVA therefore usually consists of how many tests

Answer 16

two types of tests

Question 17

ANOVA therefore usually consists of two types of tests what are are they

Answer 17

Overall F-test

Post-hoc tests

Question 18

what does Overall F-test show

Answer 18

is H0 false?

Question 19

what do Post-hoc tests show

Answer 19

Post-hoc tests to look at pairs of groups

Better Type I error control
Only interpretted if the overall F -test is significant

Question 20

ANOVA stands for what

Answer 20

ANalysis Of VAriance

Question 21

what are the 3 steps of ANOVA

Answer 21

1 Divides the variance observed in data into different parts resulting from different sources
2 Assesses the relative magnitude of the different parts of variance
3 Examines whether a particular part of the variance is greater than
expectation under the null hypothesis

Question 22

how many types of variance ar din one way ANOVA

Answer 22

There are TWO sources of variance

Question 23

what are the TWO sources of variance

Answer 23

The variance explained by the model (MSM)

The variance within groups, or the residual variance (MSR)

Question 24

what is The variance explained by the model (MSM)

Answer 24

MS = mean squares (“mean” of sum of squared deviations)
The subscript “M” stands for “model”
This is variance between groups that is due to the IV, or different treatments/levels of a factor

Question 25

what is The variance within groups, or the residual variance (MSR)

Answer 25

Within each group, there is some random variation in the scores for the
subjects

Question 26

We can assess the relative magnitude of the two different parts of variance which what

Answer 26

the F -statistic (or F ratio)

Question 27

If group means differ from each other, MSM tends to bewhat compared to MSR

Answer 27

large

Question 28

If group means differ from each other, MSM tends to be large compared to MSR, and in turn F tends to be what

Answer 28

large

Question 29

If F is found to be significantly large, this may be evidence for what

Answer 29

rejection of the null hypothesis

Question 30

The F-statistic follows a what distribution

Answer 30

F distribution

Question 31

The F-statistic follows an F distribution which varies in shape according to what

Answer 31

dfM and dfR

Question 32

what is dfM

Answer 32

between group or model degrees of freedom

Question 33

what is dfR -

Answer 33

within group or residual degrees of freedom

Question 34

The F distribution is skewed hw

Answer 34

right-skewed distribution used most commonly in ANOVA

Question 35

When referencing the F distribution, dfM or dfR is given first

Answer 35

dfM = df for numerator (sometimes: df1)
dfR = df for denominator (sometimes: df2

Question 36

With only two groups what can be used for testing for a significant difference between means

Answer 36

either a t test or an F test

Question 37

With only two groups, either a t test or an F test can be used for testing for a significant difference between means
Both procedures lead to what conclusion

Answer 37

the same one

Question 38

When the number of groups is 2, then F = what

Answer 38

= t^2