Advanced Research Methods- Chapter 12: The Correlational Research Strategy

Goals of correlational research

To establish if a statistically significant relationship exists between variables. To describe the nature of the relationship.

Correlational research

One group of participants with 2 scores from each individual. Correlation coefficients. Can make statistics predictions.

Differential research (nonexp.)

Involves multiple groups of scores and focuses on the difference between groups. T-tests and ANOVA’s.

Stats for numerical scores

X and Y. Can be made into list or scatterplot.

Correlation coefficient

Measures and describes the relationship between 2 variables. Direction, Form, and Consistency/strength.

Direction of relationship

\+: 2 variables change in the same direction. -: 2 variables change in opposite directions.

Form of relationship

Linear: Data points in scatterplot make a straight line. (Pearson’s r: measures linear relationships). Nonlinear: A relationship that is consistently one-directional, either + or -. (Spearman’s p: measures monotonic relationships).

Strength of relationship

Correlation coefficient: +/- shows direction of relationship, type of correlation (Pearson/spearman) shows form of relationship, numerical value (0.0-1.0) indicates strength.

Stats for one numerical score and one-nonnumerical score

Differential method: t-test and ANOVA.

Stats for nonnumerical

Evaluate by organizing the data in a matrix. Use chi-square.