random things to study for final

Question 1

The term experimental design refers to what?

Answer 1

Experimental design refers to-
a randomization plan for assigning participants to experimental conditions,
and the statistical analysis associated with the plan.

Question 2

What is the simplest ANOVA design?

Answer 2

The simplest design for analysis of variance is a completely randomized design (a CR-p design)

Question 3

Randomized block design (RB-p)

Answer 3

uses the blocking procedure to reduce the variance of the error effects and thereby obtain a more powerful test of a false null hypothesis.

Question 4

error effects include

Answer 4

effects that are unique to a participant, effects that are attributable to chance fluctuations in the participants performance, and effects attributable to environmental and other uncontrolled conditions.

Question 5

when is it necessary to form blocks of participants?

Answer 5

when you want to include a nuisance variable as a factor in the experiment (which is one of the three approaches for controlling nuisance variables) it is necessary to form blocks of participants

Question 6

good blocking variables in randomized block designs have the following characteristics.

Answer 6

a blocking variable can be any variable that is positively correlated with the dependent variable.

Question 7

how does blocking reduce the influence of the nuisance variable?

Answer 7

Anything that you do not control for in a study or experiment ends up in the error term of your analysis (i.e., MS error of your ANOVA). As Kirk discusses on pp. 430-431, there are various ways to control for nuisance variables. Blocking on a factor that is related to the DV has the effect of reducing the error term in the ANOVA. When you reduce the error in an ANOVA, the resulting F statistic is larger than it would have been otherwise. The blocking factor in an experiment should be related (i.e., correlated) to the dependent variable.

Question 8

an advantage of randomized block design over a completely randomized design is

Answer 8

greater power?
-RB-p design is more powerful than completely randomized design because it partitions SSWG (error effects) into two parts: SSBL and SSWG

Question 9

the effectiveness of the blocking procedure is determined by what?

Answer 9

the effectiveness of a blocking procedure is determined by how well participants in each block are matched.
-because the better the matching the higher the mean correlation between all pairs of treatment levels and the more powerful the RB-p design relative to a CR-p design.

Question 10

practical significance for CR-p design

Answer 10

omega squared is a measure of strength of association that is reported with the ANOVA F test

Question 11

practical significance for RB-p design

Answer 11

partial omega squared is used as a measure of strength of association between the dependent variable X and treatment A.

Question 12

as usual hedges g is used

Answer 12

to assess the effect size of contrasts among the treatment means

Question 13

the participants in a completely randomized factorial design are always simultaneously exposed to

Answer 13

one level each of two or more treatments

Question 14

treatment combination in a CRF-pq design is…

Answer 14

the combination of conditions to which a participant is simultaneously exposed

Question 15

the levels of treatment in a factorial design are completely crossed, which means…

Answer 15

each level of one treatment occurs once with each level of the other treatments and vice versa.

Question 16

two treatments are said to interact if

Answer 16

if differences in performance under the levels of one treatment are different at two or more levels of the other treatments

Question 17

a significant interaction between two treatments is always a signal that

Answer 17

a graph will reveal at least two non parallel lines between at least two levels of a treatment and interpretation of tests of the treatments must be qualified.

Question 18

The statisticˆω2X|A·B,AB is a measure of the

Answer 18

Practical significance of A, ignoring B andAB

Question 19

3 major disadvantages of factorial designs?

Answer 19

they may require a prohibitive number of participants
they may be difficult to interpret if interaction effects are present
and they commit an investigator to a relatively large experiment