home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Business Shareware
/
Business Shareware.iso
/
start
/
finance
/
spcex_1
/
define.hyp
< prev
next >
Wrap
Text File
|
1992-10-09
|
12KB
|
398 lines
@
SPC Abbreviations
SPC Abbreviations
C - Average count per subgroup
CDF - Cumulative Distribution Function
Cp - Capability index
Cpl - Capability index with respect to
the LSL
Cpk - Capability index (minimum of Cpl
and Cpu)
Cpu - Capability index with respect to
the USL
LCL - Lower Control Limit
LSL - Lower Specifications Limit
Max - Maximum
Min - Minimum
MR - Moving Range
P - Fraction Defective
PN - Percent Defective
R - Range
Rel Var - Relative Variation
S - Standard Deviation
SPC - Statistical Process Control
Stats - Statistics
T - Time
U - Average rate of defects per unit
UCL - Upper Control Limit
USL - Upper Specification Limit process
within specs.
XBAR - XBAR is the mean (average) of X
XMR - Individual Moving Range
@
SPC Definitions
SPC Definitions
#mBeta#m
#mC Chart#m
#mCapability Statistics#m
#mCDF#m
#mCenter/Center Line#m
#mControl Chart#m
#mCorrelation#m
#mCp#m
#mCpk#m
#mCpl#m
#mCpu#m
#mData Bin#m
#mDistribution Graph#m
#mF Value#m
#mFrequency Polygon#m
#mGamma#m
#mGraduated Scale#m
#mIndividual Moving Range (XMR) Chart#m
#mLower Specifications Limit (LSL)#m
#mLower Control Limit (LCL)#m
#mLimits#m
#mMaximum (Max)#m
#mMean#m
#mMedian#m
#mMinimum (Min)#m
#mMoving Range (MR) Chart#m
#mMu#m
#mNominal#m
#mOgive#m
#mOutlier#m
#mPatterns#m
#mP Chart#m
#mPN Chart#m
#mPop sigma(n-1)#m
#mPopulation#m
#mProcess Specifications#m
#mr2#m
#mRange#m
#mR Chart#m
#mRegression Statistics#m
#mRegression Formula#m
#mRelative Variation#m
#mSample#m
#mS Chart#m
#msigma(n)#m
#msigma(n-1)#m
#mSkewness#m
#mStatistical Process Control (SPC)#m
#mStatistics#m
#mSummary Statistics#m
#mt Value#m
#mTable Lookup#m
#mU Chart#m
#mUpper Control Limit (UCL)#m
#mUpper Specifications Limit (USL)#m
#mXBAR Chart#m
#mXBAR-R Chart#m
#mXBAR-S Chart#m
#mZones#m
@
Beta
Beta - The shape parameter in the Weibull distribution.
@
C Chart
C Chart - C is the average count per subgroup. The C control chart
displays the number of defects which appear in samples of fixed
size. C charts are based on a Poisson distribution.
@
Capability Statistics
Capability Statistics - Indices that define the degree to which the
process is or is not meeting the specifications. These include
Cpl, Cpu, Cpk, and Cp.
@
CDF
CDF - Cumulative Distribution Function. The cumulative
distribution function for a random variable X defined for any real
x by the probability X<x. An Ogive is the graph of a cumulative
distribution function.
@
Center/Center Line
Center/Center Line - A horizontal graphical line designating the
mean or median of the process measurements.
@
Control Chart
Control Chart - A tool for detecting uncontrolled variation. There
are based on the laws of probability and statistics and are
effective at detecting the presence of uncontrolled variation in
any process. The SPC software control charts are: X (Run),
XBAR-R, X Moving Range, XBAR-S, PN, P, C, U, XBAR, R, S and Moving
Range.
@
Correlation
Correlation - The degree to which one variable is related to
another. This statistic can either be negative or positive
depending on the slope of the line.
@
Cp
Cp - A process capability index which is a ratio of the
specification range (USL-LSL) to the standard deviation of the
process.
@
Cpk
Cpk - This statistic is the minimum of the Cpl and Cpu statistics.
It indicates whether to not the process being analyzed is capable
of producing little or no defects. The higher the number, the less
likely it will be that defectives are produced.
@
Cpl
Cpl - This statistic relates the difference between the center line
and the LSL to the standard deviation.
@
Cpu
Cpu - This statistic relates the difference between the USL and the
center line to the standard deviation.
@
Data Bin
Data Bin - This is a group or class of data points. Each bar on a
histogram represents a data bin.
@
Distribution Graph
Distribution Graph - A representation of the data where points are
plotted according to the value and frequency of occurrence. In the
SPC software, distribution graphs include histograms, frequency
polygons and CDFs (Ogives).
@
F Value
F Value - A ratio of the regression mean square to the error mean
square. It is used to make inferences as to whether or not a
relationship exists between x and y based on the analysis of
variance approach.
@
Frequency Polygon
Frequency Polygon - A line graph connecting the midpoints of each
class in a data set plotted at a height corresponding to the
frequency of the curve.
@
Gamma
Gamma - The location parameter in the Weibull distribution.
@
Graduated Scale
Graduated Scale - A y-axis labeling convention where the y-axis is
labelled in incremental units. The scale of these intervals will
be determined by the computer based on the number of data points.
@
Individual Moving Range (XMR) Chart
Individual Moving Range (XMR) Chart - A chart produced by
continuously plotting the range between current and previous
individual measurements.
@
Lower Specifications Limit (LSL)
Lower Specifications Limit (LSL) - A user-defined quantity which
identifies the lowest acceptable value of a product attribute.
@
Lower Control Limit (LCL)
Lower Control Limit (LCL) - A statistically determined value which
appears as a horizontal dashed line below the process average.
Generally considered to be three times the standard deviation of
the process measurements.
@
Limits
Limits - Boundaries which indicate the acceptable ranges for a
product attribute. These limits are either provided by the user or
calculated based on the process measurements in the raw data file.
@
Maximum (Max)
Maximum (Max) - The greatest quantity or value measured.
@
Mean
Mean - The arithmetic average of a set of numbers.
@
Median
Median - The dividing point where exactly half of the data values
are above and half are below.
@
Minimum (Min)
Minimum (Min) - The least quantity or value measured.
@
Moving Range (MR) Chart
Moving Range (MR) Chart - A chart produced by continuously plotting
the range between the current and previous sample means.
@
Mu
Mu - A parameter which refers to the mean of a distribution.
@
Nominal
Nominal - The user-defined target value of a process.
@
Ogive
Ogive - An Ogive is the graph of a cumulative distribution
function (CDF).
@
Outlier
Outlier - A data point which lies outside the relevant range. This
can be an indication of a severe disturbance in the process or a
data entry problem. Marking an item as an outlier can serves as a
flag to the user that something is potentially wrong.
@
Patterns
Patterns - Traits or other observable features characterizing a
data set. These include runs, freak points, freak patterns,
stratification, trends, shifts, and cycles.
@
P Chart
P Chart - P is the fraction of defectives in each group. The P
Chart is based on a running record of the proportion of defective
product in a subgroup. It shows the characteristics of both the
mean (average) and dispersion (spread) of the process.
@
PN Chart
PN Chart - PN Charts show the number of defectives in identical
groups. They are used whenever the data is binomially distributed
and the sample size is constant. PN Charts show the
characteristics of both the mean (average) and dispersion (spread)
of the process.
@
Pop sigma(n-1)
Pop sigma(n-1) - The standard deviation of all the individual
measurements.
@
Population
Population - A collection of all the items under study.
@
Process Specifications
Process Specifications - Values used to identify the acceptable
ranges for product attributes. These include LSL, USL, and
nominal.
@
r2
r2 - Sample coefficient of determination. It can be interpreted as
the proportionate reduction of the total variation associated with
the independent variable.
@
Range
Range - The difference between the largest and smallest of a data
set.
@
R Chart
R Chart - R is the range of the data in each sample. The R Chart
shows changes in the dispersion (spread) of the process.
@
Regression Statistics
Regression Statistics - The statistics which are associated with
regression analysis. Regression analysis is the general process of
predicting one variable from another. The regression statistics
include the regression line, the coefficient of determination (r2),
F-value and t-value.
@
Regression Formula
Regression Formula - Often referred to as the regression line or
fitted line. The formula describing the "best" line that minimizes
the distance between that line and the process data points.
@
Relative Variation
Relative Variation - A ratio of the sample's unbiased standard
deviation to its mean. Often used as a comparison between
processes which have the same mean.
@
Sample
Sample - A representative collection of some, but not all, of the
items of the population. Samples are used in describing the
population.
@
S Chart
S Chart - S is the sample standard deviation. The S Chart shows
changes in the dispersion (spread) of the measurements.
@
sigma(n)
sigma(n) - The biased standard deviation estimator. Bias implies
n degrees of freedom. Generally, sigma(n) is used unless the
sample size is small in relation to the population as a whole.
@
sigma(n-1)
sigma(n-1) - The unbiased standard deviation estimator. The
estimator has n-1 degrees of freedom. Sigma(n-1) is used when the
sample size is small in relation to the population as a whole.
@
Skewness
Skewness - This statistic measures the asymmetry of a process.
This occurs when values in the frequency distribution are
concentrated at either the low end or high end of the measurement
scale on the horizontal axis.
@
Statistical Process Control (SPC)
Statistical Process Control (SPC) - The use of statistical
techniques to analyze a process or its output so as to take
appropriate actions to achieve and maintain a state of statistical
control and to improve the capability of the process.
@
Statistics
Statistics - A branch of mathematics dealing with the collection,
analysis, interpretation, and presentation of masses of numerical
data.
@
Summary Statistics
Summary Statistics - The basic statistics associated with the
process. These include the mean, median, max, min, sigma, etc.
@
t Value
t Value - A ratio of the slope of the fitted regression line to its
standard deviation. Generally used as a test statistic to
determine whether or not the true slope of the process equals some
specified non zero value.
@
Table Lookup
Table Lookup - In SPC this term refers to the standard textbook
generated table constants reference.
@
U Chart
U Chart - U is the average rate of defects per unit. The U Chart
displays a rate of defects when sample size is not constant. The
chart may or may not be based on a Poisson distribution.
@
Upper Control Limit (UCL)
Upper Control Limit (UCL) - A statistically determined measurement
which appears as a horizontal dashed line above the process
average. Generally considered to be three times the standard
deviation of the process measurements.
@
Upper Specifications Limit (USL)
Upper Specifications Limit (USL) - A user-defined quantity which
identifies the highest acceptable value of a product attribute.
@
XBAR Chart
XBAR Chart - XBAR is the sample mean. The XBAR Chart shows changes
in the mean value of the process.
@
XBAR-R Chart
XBAR-R Chart - The XBAR-R control chart shows both the mean value
(XBAR) Chart and the range (R) Chart.
@
XBAR-S Chart
XBAR-S Chart - The XBAR-S control chart shows both the mean value
(XBAR) Chart and the standard deviation (S) Chart. They should be
used when the logical group size is larger than ten.
@
Zones
Zones - Areas between the 1-, 2- and 3-sigma lines above and below
the center line.
@