Chapter 8: Experimental design

Question 1

random assignment/ experimental control

Answer 1

if the scores of the groups are different, the researcher can conclude that the independent vraible cause the results becaus ethe only difference between the groups is the manipulated, independent variable

Question 2

confounding vairable

Answer 2

varies along with the indepent variables; confounding occurs when the effects that you cannot determinewith of the variables is responsible for the obseration

Question 3

internal validity

Answer 3

when the results of an experiment can confidently be attributed to the efect of the independent variable

Question 4

what are some of the must’s in research using experimental design?

Answer 4

1. obtain two equivalent groups of participatns 2. introduce the indepedent variable 3. measure the effect of the independent variable on the dependent variable

Question 5

selection differences

Answer 5

the people selected to be in the conditions cannot differe in any systematic way

Question 6

pretest-postest Design

Answer 6

when researchers use a pretest before the manipulation is introduce. Then the pretest scores are compared to the posttest scores

Question 7

posttest only design

Answer 7

when no pretest is given and only tested after the independent variable is manipulated

Question 8

what are three main reasons that researchers use a pretest?

Answer 8

1. pretest enables the researcher to asses whether the groups were already equivelant on some critical variable before the manipulation began. 2. a pretest may be necessary to select the participants to include in the research 3. whenever there is a possiblitity that participants will drop out of the experiment

Question 9

mortality

Answer 9

the dropout factor in experiment

Question 10

what are three disavantages to pretest?

Answer 10

1. time-cousuming thus higher motality rate 2. reactivity 3. deception?

Question 11

Solomon’s four group design

Answer 11

There are four possibilities when administering a pretest. This is called Solomon’s Four-Group Design. There are two main groups, namely those who received the pretest and those who did not.If there is no difference between those who received the pretest and those who did not, then we can conclude that the post-test scores will be similar

Question 12

repeated measures design/ also called within subjects design

Answer 12

particpatns are repeatedly measured on the dependent variable after being in each condition of the experiment

Question 13

what are three advantages to the repeated measure design?

Answer 13

1. The obvious advantage is that the researcher will require fewer participants since each will take on multiple roles at different times 2.This is an attractive advantage when recruitment becomes difficult 3. Another advantage is that the repeated measures design can quickly notice any differences between the groups since the experiment is repeated

Question 14

what are three disavantages to the repeated measure design?

Answer 14

1. The tasks involved can have an effect. This is called order effect.
2. If the participant is repeated the same task, their performance will likely improve (practice makes perfect). This is called practice effect.
3. If the participant is doing the same task over and over, they likely will become bored or tired. This is called the fatigue effect

Question 15

order effect

Answer 15

the order of presenting the treatments affects the dependent variable

Question 16

practive effect

Answer 16

is an improvement in preformance as a result of the repeated practice with a task

Question 17

fatigue effect

Answer 17

is deterioration in performance as the research partcipant becoems tire, bored, or distracted

Question 18

contrast effect

Answer 18

occurs when the response ot the second condition in the experiemnt is altered because the two conditions are contrasted to one another

Question 19

Counterbalancing

Answer 19

all posible orders of presentation are included in the experiment

Question 20

Partial Conterbalancing/ Latin squares

Answer 20

a limited set orders constructed to ensure 1. each condition appears at each odinal position and 2. each condition procedes and follows each condition one time

Question 21

what are the two major advantages to repeated measure designs?

Answer 21

1. a reduction in the number of participants required to complete the experiment 2. the abilit to remove random eorror due to individual differences among partcipants and tus greater ability to detect any effect of the independent variable

Question 22

what are some of the repeated measures designs?

Answer 22

counterbalancing and latin sqaures

Question 23

matched pairs desing

Answer 23

instead of simply randomly assigning participants to groups, the goal is to first match people on a partcipant characteristic.

Question 24

what is one of the first steps to the matching pairs design

Answer 24

have a matching variable, and rank order them from highest to lowest based on their scores

Question 25

what is the main advantage to the matched pair design?

Answer 25

it might be worwhile when individual differences on the dependent variable are expeted to be vvery large