6SIGMA术语列表解释[教学]

RANDOM SAMPLING: a commonly used sampling technique in which sample units are selected in such a manner that 0 combinations of n units under consideration have an equal chance of being selected as the sample.

RANGE CHART: a control chart in which the subgroup range, R, is used to evaluate the stability of the variability within a process

REGRESSION: a statistical technique for determining the best mathematical expression describing the functional relationship between one response and one or more independent variables.

RELIABILITY: the probability of a product performing its intended function under stated conditions without failure for a given period of time

REPEATABILITY: the extent to which repeated measurements of a particular object with a particular instrument produce the same value.

REPLICATION: the repetition of the set of all the treatment combinations to be compared in an experiment. Each of the repetitions is called a replicate.

REPRODUCIBILITY: the variation between individual people taking the same measurement and using the same gauging.

RESIDUAL: the difference between an observed value and a predicted value.

ROBUSTNESS: the condition of a product or process design that remains relatively stable with a minimum of variation even though factors that influence operations or usage, such as environment and wear, are constantly changing

ROIC: Return On Invested Capital

RUN CHART: a basic graphical tool that charts a process over time recording either individual readings or averages over time.

S CHART: sample standard deviation chart

SAMPLE: a group of units, portion of material, or observations taken from a larger collection of units, quantity of material, or observations that serves to provide information that may be used as a basis for making a decision concerning the larger quantity.

SAMPLE SIZE: the number of elements or units in a sample.

SAMPLE STANDARD DEVIATION CHART: a control chart in which the subgroup standard deviation, s, is used to evaluate the stability of the variability within a process.

SCATTER DIAGRAM: a graphical technique to analyze the relationship between two variables. Two sets of data are plotted on a graph, with the y-axis being used for the variable to be predicted and the x-axis being
Used for the variable to make the prediction. The graph will show possible relationships (although two variables might appear to be related, they might not be-those who know most about the variables must make that evaluation). The scatter diagram is one of the seven tools of quality.

SEVEN TOOLS OF QUALITY: tools that help organizations understand their processes in order to improve them. The tools are the cause-and-effect diagrams, check sheet, control chart, flowchart, histogram, Pareto chart, and scatter diagram.

SIGMA: s, the standard deviation of a statistical population.

SIGMA QUALITY LEVEL: a commonly used measure of process capability that represents the number of standard deviations between the center of a process and the closest specification limit.

SIX SIGMA: Please see the section “Six Sigma Quality”.

SIX-SIGMA QUALITY: a term used to generally indicate that a process is well within specifications, i.e., that the specification range is ±6 standard deviations. The term is usually associated with Motorola, which named one of its key operational initiatives "Six Sigma Quality."

SKEWNESS: a measure of the symmetry of a distribution. A positive value indicates that the distribution has a greater tendency to tail to the right (positively skewed or skewed to the right), and a negative value indicates a greater tendency of the distribution to tafl to the left (negatively skewed or skewed to the left). Skewness is 0 for a normal distribution.

SPECIAL CAUSES: causes of variation that arise because of special circumstances. They are not an inherent part of a process. Special causes are also referred to as assignable causes. (See also "common causes.")

SPECIFICATION: a document that states the requirements to which a given product or service must conform.

SPECIFICATION LIMITS: the bounds of acceptable values for a given product or process. They should be customer driven.

STANDARD DEVIATION: A of variability (dispersion) of observations that is the positive square root of the population variance.
STANDARDIZED NORMAL DISTRIBUTION: a normal distribution or a random variable having a mean and standard deviation of 0 and 1 respectively. It is denoted by the symbol Z and is also called the Z distribution.
STATISTIC: a quantity calculated from a sample of observations, most often to form an estimate of some population parameter.

STATISTICAL INFERENCE: the process of drawing conclusions about a population on the basis of statistics.

STATISTICAL PROCESS CONTROL (SPC): the application of statistical techniques to control a process. Often the term "statistical quality control" is used interchangeably with "statistical process control."

T DISTRIBUTION: a symmetric, bell-shaped distribution that resembles the standardized normal (or Z) distribution, but it typically has more area in its tails than does the Z distribution. That is, it has greater variability than the Z distribution.

T TEST: a hypothesis test of population means when small samples are involved.

TAMPERING: action taken to compensate for variation within the control limits of a stable system. Tampering increases rather than decreases variation, as evidenced in the funnel experiment.

TEST STATISTIC: a single value, which combines the evidence obtained from sample data. The P-value in a hypothesis test is directly related to this value.

TOLERANCE: the permissible range of variation in a particular dimension of a product. Tolerances are often set by engineering requirements to ensure components will function together properly. In DOE, tolerance is a measure (from 0 to 1) of the independence among independent variables.

TREND CONTROL CHART: a control chart in which the deviation of the subgroup average, X-bar, from an expected trend in the process level is used to evaluate the stability of a process

TUKEY TEST: A statistical test to measure the difference between several means and tell the user which ones are statistically different from the rest.

TYPE I ERROR: an incorrect decision to reject something (such as a statistical hypothesis or a lot of products) when it is acceptable

TYPE II ERROR: an incorrect decision to accept something when it is unacceptable

U CHART: count per unit chart; a control chart of the average number of defects per part in a subgroup.

UCL: upper control limit. For control charts, the upper limit below which a process statistic must remain to be in control. Typically, UCL is three standard deviations above the centerline.

VARIABLES DATA: measurement information. Control charts based on variables data include average (X-bar) chart, range (R) chart, and sample standard deviation (s) chart.

VARIATION: a change in data, a characteristic, or a function that is caused by one of four factors: special causes, common causes, tampering, or structural variation (see individual entries)

VARIANCE: a measure of variability in a data set or population. It is the square of the standard deviation.