multiple regression Flashcards
regression
Regression allows us to explore the relationship of multiple variables with the outcome we are interested in, at the same time
different forms of regression analysis
standard multiple regression/ hierarchical multiple regression/ stepwise regression/ logistic regression
variables in multiple regression (PV and CV)
To investigate the relationship of multiple predictors with one continuous outcome variable
PV
predictor variables can be continuous or categorical
CV
categorical variable must be continuous
why use multiple regression analysis
to figure out % of variance in the CV/ statistical significance/ which factors are making a unique contribution
how good is our model at explaining or
predicting the CV?
r square value range from 0 (0% of variance explained) to 1(100% or variance explained)
Standardized Beta Values (β)
can compare PVs to determine which is the strongest predictor, weakest predictor.
postive beta values
The closer the β value gets to +/-1, the stronger its predictive influence on the CV
negative beta values
The closer the β value gets to 0, the weaker its predictive influence on the CV
what do Standardised beta (β) values indicate
the number of standard deviations that scores on
the CV would change/ IF there was a one standard deviation change in the PV
Unstandardised beta value (B)
indicates the nature of the predictive relationship between the particular PV and the CV, in terms of the units that you have used to measure your data
Multicollinearity
Refers to the relationships between the predictor variables
violation of the assumption of multicollinearity
Any correlations between PVs that are greater than .9 indicate a violation of the assumption of multicollinearity
Tests for multicollinearity
- Tolerance – values less than .10 indicate possible multicollinearity
- VIF – values above 10 indicate possible multicollinearity