
CPUName:
where \( s \) is the sample standard deviation and where USL and LSL are user specified upper and lower specification limits. The specification limits define the range within which a product is considered acceptable (values outside this range indicate that a product is defective). Values less than 1 indicate that there are still some defectives. A value of 6Ss yields a range of plus or minus 3 standard deviations. For example, if the specification limits are symmetric about the mean and the calculated CP is exactly 1, this means that the specification limits fall at plus and minus 3 standard deviations from the mea (and almost all the data will fall within these limits). Values greater than 1 indicate the specification limits are even greater than 3 standard deviations from the mean while values less than 1 indicate specification limits are less than 3 standard deviations from the mean. The CPU statistic is used when only the upper specification limit is of interest. That is,
where \( \bar{x} \) is the sample mean.
where <y1> is the first response variable; <par> is a parameter where the computed CPU is stored; and where the <SUBSET/EXCEPT/FOR qualification> is optional.
LET A = CPU Y1 SUBSET TAG > 2
LET USL = <value>
SKIP 25 READ FURNACE.DAT X1 X2 X3 Y LET LSL = 460 LET USL = 660 LET A = CPU Y MULTIPLOT CORNER COORDINATES 5 5 95 95 MULTIPLOT 2 2 MULTIPLOT SCALE FACTOR 2 TITLE AUTOMATIC CPU PLOT Y X1 CPU PLOT Y X2 CPU PLOT Y X3 END OF MULTIPLOT
 
Date created: 02/07/2023 Last updated: 02/07/2023 Please email comments on this WWW page to alan.heckert@nist.gov. 