Correlation and Regression

What is a third variable in a partial correlation

Where each variables relationship with the third variable causes the relationship between the two variables

What is a partial correlation

Correlations that examine the relation between two variables after you have taken into consideration X and Y separate relationship

What is reliability

An internal consistency of a measure

What are the three reliability tests

1. Test-rated method

2. Split-Half method

3. Cronbachs Alpha

How does the test-retest method work

Test once then test later after a certain time

How does the split-Half method work

Splits the Questionnaire into two random half’s - calculates scores and correlates them

How does Cronbach’s alpha work

• measures internal reliability using individual terns

• Reliability of a measure puts limits on the strength of any relationship

What are the facts of Cronbachs Alpha

• scale reliable if a>0.7

• More Q’s can produce a bigger a

Weak reliability leads to what

Lower correlations

What does low reliability lead to

More random variation in the scores from measures which can lead to more error

What is a correlation

Looking at the relationship between two variables

What is regression

Trying to predict one variable from another variable using the model

What do we need in order to predict using regression

• predictor - IV

• Outcome - DV

• Model that uses the predictor to predict the outcome/DV - this can be an equation

What is a model

A way to describe a relationship between two (or more) variables