ISO 4259-3:2020 pdf free.Petroleum and related products一Precision of measurement methods and results一Monitoring and verification of published precision data in relation to methods of test.
3.1 proficiency testing PT evaluation of participant performance against pre-established criteria by means of interlaboratory comparisons
3.2 proficiency testing scheme PTS programme designed for the periodic evaluation of participating laboratories’ proficiency in the execution of a standard test method through the statistical analysis of their test results obtained on aliquots prepared from a single batch of homogeneous material
Note 1 to entry: The frequency of such testing varies in accordance with the scheme objective. Each execution of testing involves testing of a single batch of material. Materials typically vary from test to test. Note 2 to entry: This is also commonly referred to as the “Inter Laboratory Cross Check Programme”.
4 Proficiency testing scheme requirement 4.1 PTS provider The PTS provider shall conform to the technical and management requirements as outlined in ISO/IEC 17043.
4.2 PT homogeneity and stability of proficiency test items 4.2.1 Property homogeneity
The assessment of property homogeneity shall be performed after the proficiency test items have been packaged in the final form and before distribution to participants. Consult and follow ISO 13528:2015, Annex B, as appropriate.
4.2.2 PT data and statistics requirement
The comparison methodology in this document is intended for PT data and statistics meeting the following requirements.
a) The PT data requirements are as follows.
1) Data are obtained using a common standard test method with a published reproducibility obtained in accordance with ISO 4259-1 or equivalent.
2) Data are all numeric (i.e. do not contain results such as < xxx or > xxx).
3) A single result only is reported by each participant (i.e. no repeat).
b) The PT statistics requirements are as follows.
The following statistics are required to be provided as part of the PTS report for each round.
a) PT statistics (average and standard deviation) shall be based on at least 10 results, where at least 16 is strongly recommended, with at least 6 uniquely different values, after outlier rejection in accordance with the generalized extreme studentized deviation (GESD) as described in ISO 4259-1 or an equivalent technique.
NOTE 1 PT data with insufficient resolution due to rounding (e.g. cold flow properties of diesel fuel) can invalidate the last requirement (a minimum of six uniquely different values).
b) Data distribution is approximately normal as assessed by a generally accepted statistical technique such as Anderson-Darling (AD) or Shapiro-Wilk at the 0,01 significance level.
NOTE 2 PT data with insufficient resolution due to rounding can overestimate the normality assessment statistics.
c) PT standard deviation is calculated using the root-mean-square technique.
d) z-scores are as defined in ISO 13528:2015, 9.4.
5 Comparison of PT precision achieved to published precision
5.1 General
The comparison of PT precision achieved to published precision is carried out via a formal hypothesis test.
The parameter of interest is the standard deviation under reproducibility conditions as defined in
ISO 42 59-1.
The null hypothesis (H0) to be tested against an alternate hypothesis (H1) is outlined as follows:
— H0: standard deviation under reproducibility conditions achieved from the PT round (SRPT) is not different from that published (SR pub);
— Hl:SRPT is different from SR pub-
The statistical test to be used is the F-test on the variance ratio.ISO 4259-3 pdf download.