Dec 3 – Correlation
In correlation we ask if there is a relationship between x and y
Each individual or object must have measurements relating to 2 variables (ex.
Confidence and anxiety scores in a person to assess correlation)
If you can create a scatterplot, we can see a correlation in data and a good chance
we are doing a correlation question in the exam
Characteristics of a Correlation
Direction of a Relationship
• Positive correlation – as one score goes up on x, the score on y goes up
• Negative correlation – as x goes up, y goes down.
• Positive and negative relates to the direction of the linear relationship
Form/Shape of Relationship
• Correlations only work in linear relationships
Degree/strength of the relationship
• Correlation measures test the degree to which the data fit the model
• The greater the devialtion from the straight line, the weaker the correlation
• If you get a numerical value for a correlational coefficient that is greater than
1 or less than -1, you have made a mistake!
• As correlation goes closer to 1, correlation gets stronger
• As correlation goes closer to -1, correlation gets weaker
Where and Why do we use correlations
• We can predict someones running time based on their VO2 max level • Validity: attempt to demonstrate the v