8.1 Experimental Design

Question 0

The simplest possible ____ ____ has two variables: the independent variable and the dependent variable.

Answer 0

experimental design

Question 1

The independent variable has a minimum of two levels, an ____ group and a ____ group.

Answer 1

experimental, control

Question 2

The experimental method involves control of ____ ____, through either keeping such variables constant or using randomisation to make sure that any extraneous variable will affect both groups equally.

Answer 2

extraneous variables

Question 3

A researcher using a ____-____ design must obtain two equivalent groups of participants, introduce the independent variable, and measure the effect of the independent variable on the dependent variable.

Answer 3

posttest-only

Question 4

In a posttest-only design the procedures used must achieve equivalent groups to eliminate any potential ____ ____: the people selected to be in the conditions cannot differ in any systematic way.

Answer 4

selection differences

Question 5

In the posttest-only design the researcher must choose ___ ___ of the independent variable, such as an experimental group that receives treatment and a control group that does not.

Answer 5

two levels

Question 6

In the posttest-only design, the effect of the independent variable is ____. The same measurement procedure is used for both groups, so that the comparison of the two groups is possible.

Answer 6

measured

Question 7

In a ____ -____ design a pretest is given before experimental manipulation is introduced.

Answer 7

pretest-posttest

Question 8

The pretest-posttest design makes it possible to ascertain that the groups were, in fact, ____ at the beginning of the experiment.

Answer 8

equivalent

Question 9

With a sufficiently large sample of participants, ____ ____ will produce groups that are virtually identical in all respects.

Answer 9

random assignment

Question 10

A pre-test enables the researcher to assess whether the groups are in fact ____ to begin with.

Answer 10

equivalent

Question 11

Sometimes, a pretest is ____ to select the participants in the experiment.

Answer 11

necessary

Question 12

A pre-test is also necessary whenever there is a possibility that participants will drop out of the experiment; this is most likely to occur in a study that lasts over a long period of time. The dropout factor in experiments is called ____ or ____.

Answer 12

attrition or mortality

Question 13

Use of a pre-test enables you to asses the effects of ____; you can look at the pre-test scores of the dropouts and know whether their scores differ from the scores of the individuals completing the study.

Answer 13

attrition

Question 14

One disadvantage of a pre-test, however, is that it may be ____-____ and awkward to administer in the context of the particular experimental procedures being used.

Answer 14

time-consuming

Question 15

Perhaps most important, the pretest can ____ participants to what you’re studying, enabling them to figure out your hypothesis.

Answer 15

sensitise

Question 16

An ____ ____ design is where participants are randomly assigned to the various conditions so that each participates in only one group. A.k.a. between-subjects design.

Answer 16

independent groups

Question 17

In an experiment with two conditions, for example, each participant is assigned to both levels of the independent variable, called a ____ ____ design. Each participant is measured after receiving each level of independent variable. A.k.a. within-subjects design.

Answer 17

repeated measures

Question 18

In an independent groups design, different participants are assigned to each of the conditions using ____ ____.

Answer 18

random assignment

Question 19

In a repeated measures design, the same individuals will participate in ____ conditions.

Answer 19

both

Question 20

The repeated measures design has several advantages. An obvious one is that ____ research participants are needed, because each individual will participate in all conditions.

Answer 20

fewer

Question 21

An additional advantage of repeated measures designs is that they are extremely sensitive to finding ____ ____ ____ between groups. This is because we have data from the same people in both conditions.

Answer 21

statistically significant differences

Question 22

The major problem with the repeated measures design stems from the fact that the different conditions must be presented in a particular ____.

Answer 22

sequence

Question 23

The order of presenting the treatments can affect the dependent variable, this is called an ____ ____.

Answer 23

order effect

Question 24

Performance on a second task might improve merely because of the practice gained on the first task. This improvement is called a ____ ____, learning effect.

Answer 24

practice effect

Question 25

A deterioration in performance from the first to the second condition as the research participant becomes tired, bored, or distracted, is called a ____ ____.

Answer 25

fatigue effect

Question 26

It is also possible for the effect of the first treatment to carry over to influence the response to the second treatment, this is known as a ____ ____.

Answer 26

carryover effect

Question 27

There are two approaches to dealing with order effects. The first is to employ ____ techniques. The second is to devise a procedure with sufficient ____ between conditions.

Answer 27

counterbalancing, intervals

Question 28

With complete ____, all possible orders of presentation of the measures are included in the experiment.

Answer 28

counterbalancing

Question 29

A technique to control for order effects without having all possible orders is to construct a ____ ____.

Answer 29

Latin Square

Question 30

A latin square is a ___ __ of ____ constructed to ensure that (1) each condition appears at each ordinal position and (2) each condition precedes and follows each condition one time.

Answer 30

limited set of orders

Question 31

Using a Latin square to determine order controls for most ____ ____ without having to include all possible orders.

Answer 31

order effects

Question 32

Instead of simply randomly assigning participants to groups, in the ____ ____ design, the goal is to first match people on a particular variable.

Answer 32

matched pairs

Question 33

In the matched pairs design the matching variable will be either the ____ ____ or a variable that is strongly related to the dependent variable.

Answer 33

dependent measure

Question 34

When using a matched pairs design, the first step is to obtain a measure of the matching variable from each ____ . The participants are then rank ordered from highest to lowest based on the scores on the matching variable.

Answer 34

individual

Question 35

Researchers can form matched pairs that are approximately ____ on the characteristic (the highest two participants form the first pair, the next two form the second pair, and so on).

Answer 35

equal

Question 36

Finally, in the matched pairs design, the members of each pair are ____ assigned to the conditions in the experiment.

Answer 36

randomly

Question 37

A matched pairs design ensures that the groups are equivalent (on the matching variable) prior to introduction of the ____ ____ manipulation.

Answer 37

independent variable