container: xbar plot

[calmrat]

there will be interest for something like

http://thequalityweb.com/control.html

http://asq.org/learn-about-quality/data-collection-analysis-tools/overview/control-chart.html

[calmrat]

just migrating comments and stuff over ....

cward said "seems to make sense as a layer on top of the diffplot / rate plot more than the aggregate counts"