2.3 Explanation: Why Do People Do What They Do?

Question 1

What are Variables?

Answer 1

A statistic that describes the average difference between the measurements in a frequency distribution and the mean of that distribution.

Question 2

What does “Correlation” mean?

Answer 2

Two variables are said to “be correlated” when variations in the value of one variable are synchronized with variations in the value of the other.

Question 3

What’s the “Correlation Coefficient?”

Answer 3

A mathematical measure of both the direction and strength of a correlation, which is symbolized by the letter “r”.

Question 4

If “r” = 1, what kind of correlation is it?

Answer 4

Perfect positive correlation

Question 5

If “r” = -2.3897, what kind of correlation is it?

Answer 5

Negative correlation

Question 6

If “r” = -1, what kind of correlation is it?

Answer 6

Perfect negative correlation

Question 7

What’s a Natural Correlation?

Answer 7

A correlation observed in the world around us.

Question 8

What’s a “Third-Variable Correlation”?

Answer 8

Two variables are correlated only because each is causally related to a third variable

Question 9

A technique whereby the participants in two groups are identical in terms of a third variable.

Answer 9

Matched Samples Technique

Question 10

A technique whereby each participant is identical to one other participant in terms of a third variable

Answer 10

Matched Pairs Technique

Question 11

What’s the “Third-Variable Problem”?

Answer 11

The fact that a causal relationship between two variables cannot be inferred from the naturally occurring correlation between them because of the ever-present possibility of third-variable correlation

Question 12

What’s the solution to a Third-Variable Problem?

Answer 12

An Experiment!

Question 13

What are the two key features of Experimentation that help eliminate all the differences between groups?

Answer 13

Manipulation

Random Assignment

Question 14

What is “Manipulation”?

Answer 14

Changing a variable in order to determine its causal power.

Question 15

What’s a positive correlation?

Answer 15

Both variables increase or decrease together

Question 16

What’s a negative correlation?

Answer 16

As one variable increases, the other decreases, or vice versa.

Question 17

What is “Self-selection”?

Answer 17

A problem that occurs when anything about a participant determines whether he or she will be included in the experimental or control group.

Question 18

What is “Random Assignment”?

Answer 18

A procedure that lets chance assign participants to the experimental or the control group.

Question 19

What are Inferential Statistics?

Answer 19

They tell scientists what kinds of conclusions or inferences they can draw from observed differences between the experimental and control groups

Question 20

What is “Internal Validity”?

Answer 20

An attribute of an experiment that allows it to establish causal relationships.

Question 21

What is External Validity?

Answer 21

An attribute of an experiment in which variables have been defined in a normal, typical, or realistic way.

Question 22

What is a “Case Method”?

Answer 22

A procedure for gathering scientific information by studying a single individual.

Question 23

How does Random Sampling work?

Answer 23

A technique for choosing participants that ensures that everyone in the population has an equal chance of being included in the sample.

Question 24

What’s a Direct Replication?

Answer 24

An experiment that uses the same procedures as a previous experiment but with a new sample.