Dataplot Vol 2 Vol 1

# CC

Name:
CC (LET)
Type:
Let Subcommand
Purpose:
Compute the process capability index (CC) for a variable.
Description:
The process capability index measure the performance (i.e., the capability) of an industrial process. The CC is a variant of the CP and CPK capability indices.

$$\mbox{CC} = \max(\frac{\mbox{TARGET} - \bar{x}} {\mbox{TARGET} - \mbox{LSL}},\frac{\bar{x} - \mbox{TARGET}} {\mbox{USL}})$$

where USL and LSL are user specified upper and lower specification limits, TARGET is the target engineering limit, $$\bar{x}$$ is the sample mean of the data. For this statistic, smaller is better.

The specification limits define the range within which a product is considered acceptable (values outside this range indicate that a product is defective).

Syntax:
LET <par> = CC <y>             <SUBSET/EXCEPT/FOR qualification>
where <y> is the response variable;
<par> is a parameter where the computed CC is stored;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.
Examples:
LET A = CC Y1
LET A = CC Y1 SUBSET TAG > 2
Note:
The upper and lower specification limits and target value must be specified by the user as follows:

LET LSL = <value>
LET USL = <value>
LET TARGET = <value>
Note:
Dataplot statistics can be used in a number of commands. For details, enter

Default:
None
Synonyms:
None
Related Commands:
 CONTROL CHART = Generate a control chart. STATISTIC PLOT = Generate a statistic versus subset plot. DEX ... PLOT = Generate a dex plot. CP = Compute the process capability index. CPK = Compute the process capability index. CNPK = Compute the process capability index. CPM = Compute the process capability index. PERCENT DEFECTIVE = Compute the percentage of defectives in a sample. EXPECTED LOSS = Compute the expected loss of a sample.
Reference:
Kaoru Ishikawa (1982), "Guide to Quality Control," Asian Productivity Organization, (chapter 13).
Applications:
Quality Control
Implementation Date:
1998/12
Program:
SKIP 25
LET USL = 0.995
LET USL = 1.005
LET TARGET = 1.0
CHARACTER X BLANK
LINE BLANK SOLID
TITLE AUTOMATIC
XTIC OFFSET 0.5 0.5
TIC OFFSET UNITS DATA
CC PLOT Y X

NIST is an agency of the U.S. Commerce Department.

Date created: 6/5/2001
Last updated: 11/02/2015