Chapter 7.1 Cause and Effect Relationships

The goal of the experimental research strategy?

to establish that a cause-and-effect relationship exist between TWO variables

True Experiment

it must demonstrate that changes in one variable is changing the other variable

Four Basic Elements of Experiments

manipulation, measurement, comparison, control

Manipulation

changing a variable to create a set of two or more treatment conditions

Measurement

a second variable is measured for a group of participants resulting in a set of scores for each treatment condition

Comparison

the scores in one treatment condition are compared with scores in another condition

Control

all variables are controlled so that they DON'T influence the two variables being examined

Independent variable

the manipulated variable (causes)

Treatment Condition

a situation or environment characterized by one specific value of the manipulated variable

Dependent Variable

the variable observed for the outcome of the manipulation of the independent variable

Extraneous Variable

all other variables in the study that are NOT the independent and dependent

The third-variable problem

A problem that occurs when the researcher cannot directly manipulate variables; as a result, the researcher cannot be confident that another, unmeasured variable is not the actual cause of differences in the variables of interest.

Directionality problem

the researchers find a relationship between two variables, but they cannot determine which variable may have caused changes in the other variable

An experiment must control nature to establish a cause-and-effect relationship, True or False?

True, the two variables must be isolated from the influence of other variables so the exact relationship can be clear