Chart Type

Displays

XBAR

The mean of the characteristic values in the subgroup.

XBAR-MR

An XBAR chart and a moving range (MR) chart. An MR chart plots the difference between the range value for the subgroup and the previous subgroup. This chart is often used with a subgroup size of one, known as an XBAR-Individual Moving Range.

XBAR-RANGE

An XBAR chart and a range chart. A range chart plots the range of the characteristic values within the subgroup and requires a subgroup greater than one.

XBAR-SDEV

An XBAR chart and a standard deviation chart. A standard deviation chart plots the standard deviation of the characteristic values in the subgroup and requires a subgroup greater than one.

Exponentially weighted moving average

EWMA

A weighted average of all past and current observations.

EWMA-RANGE

An EWMA chart and a moving range chart.

EWMA-SDEV

An EWMA chart and a standard deviation chart.

MEDIAN

The median value for the subgroup.

MEDIAN-RANGE

A median chart and a moving range chart.

HISTOGRAM

The distribution of a process shown by plotting the relative frequency of an event within a process versus the possible process outcomes.

BOX-WHISKER

The spread of data for all visible characteristics using the median set of data, the inter-quartile range, and the extreme values. Also known as a boxplot.

P

The fraction of defective units per total units in the sample.

NP

The number of defective units in the sample.

C

The total number of defects in the sample.

U

The average number of defects per unit.