Components of a Variance Model for the Analysis of Repeated Measurements in Fixed-Point Comparisons |
| |
Authors: | Eduarda Filipe |
| |
Affiliation: | 1.Laboratório Central de Metrologia,Instituto Português da Qualidade,Caparica,Portugal |
| |
Abstract: | Experimental design is a statistical tool concerned with the planning of experiments to obtain the maximum amount of information
from the available resources. This tool may be applied to metrology, especially for the analysis of a large number of repeated
measurements (replicates) of short-term repeatability and the medium-term and long-term reproducibilities, enabling the inclusion
of these “time-dependent sources of variability” in the uncertainty budget. The realization of the International Temperature
Scale of 1990 (ITS-90) scale requires that laboratories usually have more than one cell for each fixed point, for comparison
on a regular basis. The calculation of the uncertainty of such comparisons is considered here, taking into account these time-dependent
sources of variability. These components of the uncertainty evaluated by a Type A method are obtained by the statistical analysis
of the experimental results using the components of a variance model for designs consisting of nested or hierarchical sequences
of measurements, as foreseen by the mainstream GUM. An application example of a balanced nested structure in the comparison
of two fixed-point cells is presented. |
| |
Keywords: | Experimental design Nested structures Uncertainty |
本文献已被 SpringerLink 等数据库收录! |
|