Dictionary · Statistics
Z-score
A proficiency-testing statistic z = (x − X)/σ_pt comparing a participant result with the assigned value in units of the standard deviation for proficiency assessment; |z| ≤ 2 is conventionally satisfactory.
Related terms
More from Statistics
Gauge R&R
A measurement systems analysis estimating the variation due to the gauge (repeatability) and the operators (reproducibility), commonly expressed as a percentage of total variation or tolerance.
AIAG MSA manual
Repeatability condition of measurement
A condition set that includes the same procedure, operators, measuring system, operating conditions, and location, with replicates over a short period.
VIM (JCGM 200:2012) 2.20
Measurement precision
Closeness of agreement between indications or measured values from replicate measurements under specified conditions — usually expressed as a standard deviation, variance, or coefficient of variation.
VIM (JCGM 200:2012) 2.15
Measurement bias
The estimate of a systematic measurement error — typically the difference between the mean of repeated indications and an accepted reference value.
VIM (JCGM 200:2012) 2.18
Measurement reproducibility
Measurement precision under reproducibility conditions — what interlaboratory comparisons quantify.
VIM (JCGM 200:2012) 2.25
Measurement repeatability
Measurement precision under repeatability conditions — the tightest, most flattering precision an instrument and operator can show.
VIM (JCGM 200:2012) 2.21