Chapter 8: Bivariate Correlational Research

How can you test an association claim?

• With a bivariate correlational research design

  • ^A relationship between 2 variables

What is a bivariate correlation?

An association that involves exactly 2 variables

What does a Pearson correlation coefficient do?

Tells the strength of a correlation

How can you tell the magnitude/strength of the correlation coefficient?

The closer it is to -1 or +1, the stronger it is

What can you conclude from correlational research? (2)

• Frequency & association claims

• NOT causal claims

What are scales of measurement? (Identify categorical vs quantitative)

• Categorical: nominal

• Quantitative: ordinal, interval, ratio

What is validity?

How well the research evidence represents the claim

What are the 4 validities?

1. Construct - how well the variables are measured or manipulated

2. External - how generalizable the results are to a larger population

3. Internal - extent to which A is actually influencing B

4. Statistical - how well the numbers support the claim

Statistical validity & Pearson’s correlations (5)

• Strength of relationship → effect size (r)

• Precision of relationship → confidence intervals

• Replication of relationship → curvilinear association

• Outliers

• Restricted range - we can only see a small piece of the overall trend

Spurious correlations

Meaningless patterns/trends