Week 9 - Correlation and Regression Flashcards
Correlation
The strength, direction, shape, and significance of two continuous variables
How is correlation measured?
Pearson’s r
Pearson Correlation Co-efficient
ranges between -1 and +1, designed to test linear relationship
Regression
helps to understand the relationship between variables and making predictions based on the relationship
What is the slope?
An indication of the gradient of the line or it’s ‘steepness’
what is the Y-axis intercept?
the point at which the line of best fit crosses the Y-axis - can be positive or negative
Residuals
A residual score is the difference between the actual score and the predicted score
Measure of accuracy
Standard Error of the Estimate (SEE) - average or mean of the residual scores
Power
The ability to obtain a significant result when an effect is real
Yhat = a + (b) (X)
Regression equation
Assumptions
- normality
- linearity
Potential problems
- outliers/extreme scores
- restriction in range
