Ch 10 Experimental Research

Question 1

experiment

Answer 1

a controlled method of observation in which the value of one or more independent variables is changed to assess the casual effect on one or more dependent variables

Question 2

laboratory experiments

Answer 2

conducted in artificial settings that are constructed in such a way that selected elements of the natural environment are simulated and features of the investigation are controlled

Question 3

field experiments

Answer 3

are conducted in natural settings as people go about their everyday affairs

Question 4

experimental stimulus (or experimental treatment)

Answer 4

an independent variable that is directly manipulated by the experimenter to assess its effect on behavior

Question 5

experimental group

Answer 5

a group of subjects exposed to the experimental stimulus

Question 6

experimental condition

Answer 6

describes the group of people who receive the experimental stimulus

Question 7

symbols in logic of experimentation

Answer 7

O = observation or measurement of dependent variable
X = exposure of people to the experimental stimulus or independent variable
R = random assignment to conditions

Question 8

experimental variability

Answer 8

variation in the dependent variable produced by the independent variable and is the focus of interest in experiments

Question 9

extraneous variability

Answer 9

variation in the dependent variable from any source other than the experimental stimulus and it makes inferences about change in the dependent variable difficult

Question 10

control variables

Answer 10

variables whose value is held constant in all conditions of the experiment

Question 11

control group

Answer 11

group of research subjects who are provided the same experiences as those in the experimental condition with a single exception: the control group receives no exposure to the experimental stimulus

Question 12

control condition

Answer 12

refers to the state of being in a group that receives no experimental stimuli

Question 13

matching

Answer 13

involves matching individuals in the experimental group with similar subjects for a control group

Question 14

random assignment

Answer 14

uses chance to reduce the variation between experimental and control groups

Question 15

blocking

Answer 15

combination of matching and randomization. the subjects are first matched on one or more key variables to form blocks of similar subjects. members of each block then are randomly assigned to the experimental and control conditions

Question 16

internal validity

Answer 16

refers to whether the independent variable actually produces the effect that it appears to have had on the dependent variable ; it is concerned with ruling out extraneous sources of variability to the point where we have confidence that changes in the dependent variable are caused by independent variable

Question 17

history

Answer 17

is more of a problem for field experiments

concerns events other than the experimental stimulus that occur during the course of experiment and that could affect dependent variable

Question 18

maturation

Answer 18

refers to change occurring within experimental subjects as a result of the passage of time

Question 19

testing

Answer 19

may occur whenever subjects are exposed to a measurement device more than once

Question 20

instrumentation

Answer 20

refers to the fact that the way in which variables are measured may change in systematic ways during the course of an experiment, resulting in observations being measured differently at the end of an experiment than they were at beginning

Question 21

statistical regression

Answer 21

arises any time subjects are placed in experimental or control groups on the bias of extremely high or low scores on a measure in comparison to the average score for the whole group

Question 22

selection

Answer 22

a threat to internal validity when the kinds of people who are selected for one experimental condition differ from those who are selected for other conditions

Question 23

experimental attrition

Answer 23

occurs when there is a differential dropout of subjects from the experimental and control groups

Question 24

pre experimental designs

Answer 24

lack both the random assignment to conditions and the control groups that are such a central part of good experimental designs

Question 25

true experimental designs

Answer 25

more complex and use randomization and other techniques to control the threats to internal validity

Question 26

quasi-experimental designs

Answer 26

special designs that are used to approximate experimental control in non experimental settings

Question 27

external validity

Answer 27

concerns the extent to which casual inferences made in an experiment can be generalized to other times, settings, or groups of people

Question 28

demand characteristics

Answer 28

subtle, unprogrammed cues that communicate to subjects something about how they should behave

Question 29

experimenter’s expectations

Answer 29

can be communicated to subjects in such a subtle way that neither the experimenter nor the subjects are aware that the communication has taken place

Question 30

double blind experiment

Answer 30

neither the subjects nor the experimenter knows which people are in the experimental condition and which are in the control condition