QM #5
Exploring Assumptions
Homogeneity of Variance
💡 homogeneous
Residual
💡 The difference between the observed value of the dependent variable (y) and the predicted value (ŷ)
Skewness
💡 Unsymmetrical distribution
➖: Distribution tail on the right
➕: Distribution tail on the left
"N" > Whole sample
"n" > subsample within the whole sample
probability-probability plot (P-P plot)
quantile-quantile plot (Q-Q plot)
💡 a graphical technique for determining if two data sets come from populations with a common distribution. A q-q plot is a plot of the quantiles of the first data set against the quantiles of the second data set.
Measured using Levene's test
Categorical
Scale
Ordinal (order)
Nominal (arbitrary)
📝 Age group, etc.
📝 Likert scale questions (see Larson Hall, p. 53)
📝 Gender, marital status, etc.
Bar chart only
Bar or pie chart
Outliers