Stats and research design (internal, external validity/experimental design)

Question 1

when a study has adequate internal validity, the investigator can conclude that observed variations in the ________ variable were caused by variations in the ________ variable rather than by other factors

Answer 1

dependent; independent

Question 2

Campbell and Stanley identified several “generic” extraneous variables that can limit a study’s internal validity. _________ refers to an external event that is irrelevant to the research hypothesis but that occurs during the course of a study and affects subjects’ status on the ______ variable

Answer 2

history; dependent

Question 3

_______ refers to changes that occur within subjects during the course of a study as the result of the passage of time and that have a systematic effect on the DV

Answer 3

maturation

Question 4

Statistical _____ is the tendency for very high and very low scores to move toward the mean on retesting.

Answer 4

regression

Question 5

it threatens a study’s internal validity whenever subjects are selected to participate in the study because of their extreme scores on the _________ variable measure

Answer 5

dependent

Question 6

_______ is a problem when subjects in different treatment groups are not similar in terms of important characteristics at the beginning of the study

Answer 6

selection

Question 7

______ limits a study’s internal validity when subjects who drop out of one group differ in an important way from those who drop out of another group

Answer 7

attrition

Question 8

_____ can interact with history and threaten a study’s internal validity if one group of subjects is exposed to an external condition that does not affect subjects in other groups

Answer 8

selection

Question 9

external validity refers to the ________ of research results to other people, settings, and conditions

Answer 9

generalizability

Question 10

________ is a threat to external validity when administration of a pretest affects how subjects react to the treatment

Answer 10

pretest sensitization

Question 11

The effects of pretesting on both internal and external validity can be evaluated by using the ______ four-group design

Answer 11

Solomon

Question 12

Another potential threat to external validity is an interaction between ________ and treatment, which occurs when people in the sample differ from people in the ________ in terms of some characteristics that makes them respond differently to the IV

Answer 12

selection; population

Question 13

_______ is another potential threat to external validity and occurs when research participants act differently because they know their behaviour is being observed

Answer 13

reactivity

Question 14

A subject’s behaviour might be altered by _______, which are cues in the research setting that communicate to subjects what behaviours are expected of them

Answer 14

demand characteristics

Question 15

multiple treatment _______ threatens a study’s external validity when more than one ________ of the IVs is administered to each subject. This threat can be controlled by using a Latin square or other type of ______ design

Answer 15

interference; level; counterbalance

Question 16

when using a ______ groups research design, the effects of an independent variable are assessed by administering each level of the IV to a different ______ of subjects and comparing the performance or status of the groups on the ______ variable

Answer 16

between-; group; dependent

Question 17

when using a _______ subjects (repeated measures) design, the effects of an independent variable are assessed by comparing the performance or status of the same group of subjects on the ______ variable after receiving, at different times, each level of the IV

Answer 17

within- ; dependent

Question 18

in a single-group ________ design, the dependent variable is measured several times before and after the IV is applied

Answer 18

time-series

Question 19

A research design that includes two or more IVs is called a _______ design. an advantage of this type of design is that it allows an investigator to assess the main effects of each independent variable as well as any interaction between those variables

Answer 19

factorial

Question 20

a(n) _____ effect is the effect of one independent variable on the dependent variable

Answer 20

main

Question 21

a(n) _______ is the effect of one IV on the DV at different _______ of another IV

Answer 21

interaction; levels

Question 22

Two distinguishing characteristics of the single-subject designs are that they include at least two phases – a ______ (no treatment phase), and a _________ phase – and that they involved measuring the ______ variable at regular intervals during each phase of the study

Answer 22

baseline; treatment; dependent

Question 23

three commonly used single-subject designs are:

Answer 23

the AB design, the reversal design, and the multiple baseline design

Question 24

the AB design includes one ______ (A) phase and one ______ (B) phase

Answer 24

baseline; treatment

Question 25

the reversal designs extend the AB design by including, at a minimum, two _______ phases and one ______ phase

Answer 25

baseline; treatment

Question 26

when using a reversal design, if the subject’s performance on the ________ variable follows the predicted pattern (i.e., if it changes in the expected direction after the treatment is applied and withdrawn), a researcher can conclude that changes in the _______ variable are due to effects of the ________ variable rather than to history, maturation, or other factors

Answer 26

dependent; dependent; independent

Question 27

when it is not ethical or practical to withdraw an effective treatment during the course of a study, an investigator can use the multiple _______ design, which involves sequentially applying the ________ variable to two or more “baselines” –i.e., either to two or more behaviours, settings, tasks, or subjects. An advantage of this design is that, once the IV is applied to a baseline, it is not ______ during the study

Answer 27

baseline; independent; withdrawn (removed)

Question 28

An interviewer unintentionally nods whenever research participants answer his questions in ways that confirm the study’s research hypothesis. The interviewer’s behavior is best described as an example of which of the following?

Answer 28

demand characteristics

Question 29

A psychologist evaluates the effects of a 15-month training program on the conservation skills of preoperational children by administering a measure of conservation to the same group of children before and at the end of training. The psychologist finds that significantly more children are able to conserve after the program than before the program. The biggest threat to this study’s internal validity is:

Answer 29

Maturation

Question 30

A psychologist obtains a statistically significant F-ratio for the interaction between two independent variables (IVs). This means that:

Answer 30

the effects of one IV are contingent on the level of the second IV.

Question 31

As applied to research design, “external validity” refers to which of the following?

Answer 31

generalizability

Question 32

Dr. Angela Angst is using a repeated measures design to compare the effects of different techniques for reducing free-floating anxiety. To control potential carryover effects, Dr. Angst should use which of the following?

Answer 32

counterbalancing

Question 33

In what type of research studies do participants act as their own “controls”?

Answer 33

single-subject

Question 34

The Solomon four-group design is used to control which of the following threats to the validity of a research study?

Answer 34

pretest sensitization