correlation and regression

What is a correlation?

Pearson’s product moment correlation coefficient

Tells us the strength and direction of a relationship between 2 variables

What is a partial correlation?

When we suspect that a correlation between two variables is due to a third variable

Correlations that examine the relation between 2 variables after you have taken into consideration X and Y separate relationships with Z

What is reliability?

Internal consistency of a measure

How can you test reliability?

Test-retest method

Split-half method

Cronbach’s alpha

What is cronbachs alpha ?

Measures internal reliability using individual items

Scale reliable if a>0.7

Reliability measure puts limits on the strength of any relationship

How are reliability and correlation linked

Weak reliability= lower correlation

Low reliability=more random variation

What is a regression

Regression is trying to predict one variable from another using the model

Assuming one (the predictor) precedes the other (outcome)

What is a model

A way to describe a relationship with 2+ variables

Y=mx+c