Whether you’re new to the quality and continuous improvement arena or a seasoned expert seeking detailed information on a specific quality topic, you should find what you need in our Glossary of Terms.

Explore the concepts, tools, applications and technical terms that make up the world of continuous improvement.

R Squared

R Squared is the square of the correlation coefficient, r, and it represents the strength of a model. (1-R Squared) multiplied by 100 Percent is the percentage of noise in the data not accounted for by the model.

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Random Sample

A Random Sample is a sample collected from a population in such a way that every element of the population has an equal chance of being selected.

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Range

The Range is defined as the difference between the largest and the smallest observed values in a data set. The Range, including any Outliers, is the actual spread of data and only the largest and smallest data values are considered. The range value of a data set is greatly influenced by the presence of just one unusually large or small value Outlier. It is an informative tool used as a supplement to other measures such as the standard deviation, but it should rarely be used as the only measure of spread. The disadvantage of using range is that it does not measure the spread of the majority of values in a data set and as such should only be used to measure the spread between highest and lowest values.

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Reality Tree

The Reality Tree is a tool used to analyse cause and effect relationships in order to identify root causes.

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Regression Analysis

Regression Analysis is a statistical technique for determining the mathematical relation between a measured quantity and the variables it depends upon.

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Repeatability

Repeatability is the variation arising when all efforts are made to keep conditions constant by using the same operator and instrument over a short period of time.

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Residual

Residual is the difference between an observed value and the predicted value.

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