Section 1.2 | Data Structures, Research Methods, and Statistics

Question 1

Define:

correlational method

Answer 1

Also known as the correlationsal research strategy, in the correlational method, two different variables are observed to determined whether there is a relationship between them.

• A correlational study cannot demonstrate a cause-and-effect relationship.

Question 2

Define:

experimental method

Answer 2

Also known as the experimental research strategy, in the experimental method, one variable is manipulated while another variable is observed and measured. To Establish a cause-and-effect relationship between the two variables, an experiment attempts to control all other variables to prevent them from influencing the results.

Question 3

What are manipulation and control?

Answer 3

1. A researcher manipulates one variable by changing its value from one level to another. A second variable is observed (measured) to determine whether the manipulation causes changes to occur.
2. The researcher must exercise control over the research situation to ensure that other, extraneous variables do not influence the relationship being examined.

Question 4

Define:

participant variables

Answer 4

Participant variables are characteristics such as age, gender, and intellegence that vary from one individual to another.

• Researchers must be careful that participant variables do not differ from different groups of participants.
• Whenever a research study allows more than one explanation for the results, the study is said to be confounded because it is impossible to reach an unambiguous conclusion.

Question 5

Define:

environmental variables

Answer 5

Environmental variables are characteristics of the environment such as lighting, time of day, and weather conditions.

• Researchers must ensure that all participants are tested in the same environment, otherwise it may produce a confounded experiment.

Question 6

What are the three basic techniques that researchers use to control other variables?

Answer 6

1. Researchers use random assignment, which means that each participant has an equal chance of being assigned to each of the treatment conditions. It is also used to make sure that participant characteristics are evenly distributed between groups.
2. Matching is used to ensure equivalent groups or equivalent environments; eg. putting 60% females and 40% males in each groups.
3. The last method is simply holding the variables constant; eg. studying only 10-year-old boys.

Question 7

Define:

independent variable

Answer 7

The independent variable is the variable that is manipulated by the researcher. In behavioural research, the independent variable usually consists of the two (or more) treatment conditions to which subjects are exposed. The independent variable consists of the antecedent conditions that were manipulated prior to observing the dependent variable.

Question 8

Define:

dependent variable

Answer 8

The dependent variable is the one that is observed to assess the effect of the treatment.

Question 9

What is the main difference between the correlational method and the experimental method?

Answer 9

An experimental study evaluates the relationship between two variables by manipulating one variable (the independent variable) and measuring one variable (the dependent variable). Only one variable is actually measured. This is different from a correlational study, in which both variables are measured and the data consist of two separate scores for each individual.

Question 10

Define:

control condition

Answer 10

Individuals in a control condition do not recieve the experimental treatment. Instead, they either receive no treatment or they receive a neutral, placebo treatment. The purpose of a control condition is to provide a baseline for comparison with the experimental condition.

Question 11

Define:

experimental condition

Answer 11

Individuals in the experimental condition do recieve the experimental treatment.

Question 12

What makes an experiment experimental? What are two examples of nonexperimental studies?

Answer 12

A real experiment must include manipulation of an independent variable, and rigurous control of other, extraneous variables.

• Correlational studies are also examples of nonexperimental research.

One example of nonexperimental studies is using nonequivalent groups. For example, comparing boys to girls, 10-year-olds to 8-year-olds, or children in single-parent homes and children in two-parent homes. Because it is impossible to use techniques like random assignment to control participant variables and ensure equivalent groups, this type of research is not a true experiment.

In a pre-post study, a researcher measures two conditions: one “before” and one “after”. The researher has no control over the passage of time. Because the researcher cannot control the passage of time or other variables related to time, this study is not a true experiment.

Question 13

Define:

quasi-independent variable

Answer 13

In an nonexperimental study, the “independent variable” that is used to create the different groups of scores is often called the quasi-independent variable.

• This is because it cannot be a true independent variable, because nothing is manipulated in a nonexperimental study.