This is a comprehensive resource for analyzing and interpreting data so that the areas to improve become apparent. The tools explained are run charts, control charts, histograms, capability analysis, scatter diagrams, and Pareto diagrams.

What type of data do I have?

Variables charts (measurement data) (Learn more) Consists of measurements of a characteristic , such as length, weight, density, time, or pressure.
Control charts	Is your process stable and in control?
X-bar & range	Use this if your data has a subgroup size of 2-10 observations.
X-bar & sigma	Use this if your data has a subgroup size of 11 or more observations.
X-MR	Use this if your data has a subgroup size of 1 observation.
Median	Use this to analyze measurement data when you want to plot all observations.
Run chart	Use this to see trends and patterns if there is not enough data for a control chart.
Histogram	Use this to determine if your data has a normal distribution .
Capability analysis	Use this to determine if your process is capable of producing output within specification limits.
Attributes (counts data) (Learn more) Consists of defects per item (nonconformities ) or the number of defective items (nonconforming ). For example, the number of non-working parts in sample or the number of blemishes counted on an individual part.
Control charts	Is your process stable and in control?
np-chart	Use this if your data is a count of nonconforming units and the subgroups are all the same size.
p-chart	Use this if your data is a count of nonconformities and the subgroups are all the same size.
c-chart	Use this if your data is a count of nonconformities and the subgroups are all the same size.
u-chart	Use this if your data is a count of nonconformities and the subgroup size varies.
Capability analysis	Use this to determine capability for attributes data.
Pareto (counts in categories) (Learn more) Consists of a count of items or occurrences, such as the number of defective items, the number of scratches on a door panel, or how often a specific problem occurs.
Pareto diagram	Use this to analyze counts that are in categories.
Rare event (Learn more) Use this when other control charts are not effective to determine if your process is stable.
g-chart	Use this if your count data occurs infrequently. It is used by counting the number of events between rarely-occurring error or a nonconforming incident.
t-chart	Use this if your error or non-nonconforming incident occurs infrequently. Each point on the chart represents an amount of time that has passed since the prior nonconforming incident occurred.

Interpreting quality charts