Understanding and Comparing Distributions

Word Definition
Boxplot Displays Five Number Summary.
Central box with whiskers that extend to the non-outlying data values.
Useful for comparing groups and displaying outliers.
Lower Fence (Outlier) Q1 – 1.5(IQR)
Any datum below is lower outlier.
Upper Fence (Outlier) Q3 + 1.5(IQR)
Any datum below is upper outlier.
Far Lower Outlier Any datum below Q1 – 3(IQR)
Far Upper Outlier Any datum above Q3 + 3(IQR)
When COMPARING DISTRIBUTIONS consider their: Shape, center, outliers, and spread.
When COMPARING BOXPLOTS consider their: Shape, median, IQR, variation, outliers.
Timeplot Displays data that change over time.
Successive values are usually connected with lines to show trends more clearly.
Smooth curves can be added to show long-term patterns and trends.