Boxplots of Z Scores
- To visually scan the z scores and find unusual values, from the menus choose:
- In the Boxplot dialog, elect Summaries of separate variables.
- Click Define.
- Select Zscore: Log-long distance through Zscore: Log-wireless as the variables the boxes represent.
- Click Options.
- In the Options dialog, select Exclude cases variable by variable.
- Click Continue.
- Click OK in the Define Simple Boxplot dialog box.
Boxplots of the z scores show that customer 567 spent much more than the average customer on toll-free service last month. This should account for the larger skewness and kurtosis observed in Toll free last month.