W8: RQ for Group Differences 3

Question 1

What is an alternative name of a dependent group

Answer 1

“WIthin-Subject”/ “Repeated-measures”

Question 2

When is dependent group usually used

Answer 2

Either same people: (a) repeated occasion; (b) different condition; or matched group.

Question 3

If a participants drops out of a dependent group study, how?

Answer 3

Sample is invalid

Question 4

What do we use for preliminary analysis in a Dependent group RQ

Answer 4

Frequency count? and QQ Plot

Question 5

Does regression apply to dependent groups

Answer 5

No. “independence of observation” is violated in the regression assumption

Question 6

What is the difference in the univariate and multivariate approach. Which is better?

Answer 6

Univariate assumes sphericity; Multivariate does not. If sphericity is met, univariate > multivariate

Question 7

What is the similarity between univariate and multivariate

Answer 7

Both assume independence of observation (which violated) and normality

Question 8

What is sphericity

Answer 8

Homogeneity of variance of all possible DIFFERENCE (not observed) scores between pairs of levels

Question 9

What is compound symmetry

Answer 9

Covariance martix with: (a) same variance in each diagnoal; (b) same variance in each off-diagonal

Question 10

How does compound symmetry related to sphericity

Answer 10

Compound symmetry is a sufficient, not necessary, condition for sphericity

Question 11

What does sphericity apply to? Sample or Population

Answer 11

Both

Question 12

What is the calculation of sphericity

Answer 12

ε (episolon)

Question 13

what is ε in terms of population/sample

Answer 13

Population parameter on population covariance matrix

Sample statistic on sample covariance matrix

Question 14

what is the range of ε

Answer 14

1/k (lack sphercitiy) <= ε = 1 (perfect sphericity)

Question 15

What are the 2 ε estimators

Answer 15

1) Greenhouse-geisser estimator (Conservative) ε_ hat

2) Huynh-Feldt estimator ε wave

Question 16

In investigation of dependent group, what do we look for first

Answer 16

Look for Pillai. If p

Question 17

What are focused linear contrast in the context of >2 dependent groups

Answer 17

Orthogonal polynomial contrasts: decomposition of observed change over time into constituent component rates of change

Question 18

How many orthogonal polynomial contrast are there in 5 groups

Answer 18

K-1. 5 Groups = 4 Polynomial Contrasts

Question 19

What do we look at to investigate polynomial contrast

Answer 19

Look for pillai. If p

Question 20

is the initial investigation in R uni or multivariate . What does it mean

Answer 20

Multivariate. Confidence intervals might be affect if sphericity is not fulfilled.

Question 21

Under what variate can interval estimators for dependent groups be calculated

Answer 21

Univariate approach.

Question 22

What do we look at in confidence intervals in dependent groups

Answer 22

Look at crossing of zero