Describing the Relationship between Two Variables: Correlation Key Terms

Question 1

Correlation Coefficient

Answer 1

A measure of the strength and the direction of a linear relationship between two variables ranging from -1 (perfect negative correlation) through 0 (no correlation) to +1 (perfect positive correlation).

Question 2

Correlation Matrix

Answer 2

A common way of reporting the correlation coefficients among several variables in a research article; table in which the variables are named on the top and along the side, and the correlation among them are all shown.

Question 3

Correlation

Answer 3

A relationship between two variables.

Question 4

Correlational Research Design

Answer 4

Any research design other than a true experiment.

Question 5

Curvilinear Correlation

Answer 5

Relationship between two variables that shows up on a scatter diagram as dots following a systematic pattern that is not a straight line.

Question 6

Direction of Causality

Answer 6

Path of causal effect; if X is thought to cause Y then the direction of causality is from X to Y.

Question 7

Linear Correlation

Answer 7

Relationship between two variables that shows up on a scatter diagram as the dots roughly following a straight line.

Question 8

Negative Correlation

Answer 8

A relationship between two variables in which scores on one variable move in the opposite direction of the other; on a scatter diagram, the dots roughly follow a straight line sloping down and to the right.

Question 9

No correlation

Answer 9

Shows no systematic relationship between two variables.

Question 10

Outliers

Answer 10

Scores with an extreme (very high or very low) value in relation to the other scores in the distribution.

Question 11

Pearson correlation coefficient (r)

Answer 11

A standardized measure of the strength and direction of a relationship between two variables. You can take any value between -1 and +1.

Question 12

Positive Correlation

Answer 12

A relationship between two variables in which scores on one move in the same direction as the other; on a scatter diagram, the dots roughly follow a straight line sloping up and to the right.

Question 13

Restriction in Range

Answer 13

A situation in which you figure a correlation but only a limited range of the possible values on one of the variables is include in the group studied. This will cause the calculated correlation coefficient to be lower than it really is.

Question 14

Scatter Diagram

Answer 14

A graph showing the relationship between two variables: the values of one variable are along the horizontal axis and the values of the other variable are along the vertical axis; each score is shown as a dot in this two-dimensional space.

Question 15

Spearman’s correlation coefficient (rho)

Answer 15

A standardized measure of the strength and direction of a relationship between two variables that does not rely on the assumptions of a parametric test. It is the equivalent of Pearson’s correlation coefficient performed on data that have been converted into rank-ordered scores (ordinal data).