Multiple Regression Flashcards
regression allows us to…
predict a score for one variable based on their score on another variable
criterion variable
DV
predictor variable
IV
DV
criterion variable
IV
predictor variable
data requirements for multiple regression
Explores linear relationship between criteria and predictor variables
Criterion measured on a continuous scale
Predictors measured on a ratio, interval or ordinal scale
assumptions of MR
sample size
multicollinearity
normality
homoscedasticity
linearity
hypotheses of MR
H0 = null = no difference/no linear relationship
H1 = alternate = linear relationship with at least one predictor
Sample size assumption
Tabachnick and Fidell (2007)
N>50+8M
N is number of ppts
M is number of predictor variables
normality assumption
normality of residuals
use histogram line of best fit and pplots
what to use to test normality assumption
histogram and line of best fit
p-plots
residual
difference between predicted and observed value
linearity assumption
predictor and criterion lineally related
pplot
what to use to test linearity assumption
p-plot
multicollinearity assumption
strong correlation between C&P is wanted but not between P&P
high intercorrelation (r>+/-.90) among predictors shows multicollinearity which is bad
singularity = perfect linear relationship which is bad
VIF >0.50
Tolerance<10
these show no multicolloinearity