In this paper, the ASTM grain size number of aluminium alloy specimen was determined respectively by Abrams Three-Circle Procedure and Planimetric Procedure of ASTM E112-13 Standard, and the uncertainty of the result was evaluated. The results are as follows: 1) Using the Abrams Three-Circle Procedure determines G, G=4.13, U=0.26, k=2; Using the Planimetric Procedure determines G, G=3.94, U=0.15, k=2. 2) It is suggested that the ASTM E112 standard should provide that the errors of counting grain boundary intersection count or number of grains should be less than or equal to 2, and the ruler that determines the diameter of test circle or scale length should be with the scale that is less than or equal to 0.10 mm. On this condition, the uncertainties caused by them in determining G can be negligible. 3) The main sources of uncertainty for the determination of G by Abrams Three-Circle Procedure and Planimetric Procedure are repetitive measurement, which depends on the uniformity of grain size of specimen. 4) The %RA limit of ASTM E112 for determining G should be redefined according to the measurement uncertainty in order to be up to the precision requirement (±0.25).

To investigate the differences between industrial pairs trading in different classification levels, explore the compatibility between pure statistical pairs and industrial pairs, the article based on the 50 stock’s data of Index 50 SSE in China from 2004 to 2010, implemented the GGR trading strategy, and paired the sample stocks with pure statistical, primary industry and secondary industry pairing methods. It discovered that primary industrial pairs make no significantly difference with pure statistical pairs, but the secondary industry pairs do and improve markedly with the possibility of ruling out the best pairs arbitrarily. With GGR trading strategy established, stock selection criteria would impact on the trading results.

In this paper, the ASTM grain size number of aluminium alloy specimen was determined by the Abrams three-circle procedure and planimetric procedure, according to ASTM E112-13 standard, and the measurement uncertainty was evaluated. Based on the test data and theoretical analysis, the %RA limit for acceptability of ASTM E112 grain size measurement was discussed. The following two corrections are made: when G is determined via the Abrams three-circle and planimetric procedures, the %RA limit should not exceed 8.4% and 16.1%, respectively, instead of earlier regulated value of 10%.