Approach of credibility evaluation for testing system with small samples

Aimed at the problem that the small sample test data are lack of information and it is difficult to use probability statistic method for interval estimation, a novel approach of credibility evaluation for small sample testing system is proposed by integrating the repeated sampling method and the small sample interval estimation method. Many similar small samples with the same sample size are obtained using the theory of repeated sampling. According to the grey system theory, an improved definition and calculation method for grey confidence level and grey confidence interval is proposed. On this basis, the common area of the grey confidence intervals of many small samples is calculated, which is the grey confidence interval for the original small sample data. Under the same confidence level, the above confidence interval has narrower interval width and higher precision. The rationality and validity of the above method is verified through example simulation, which provides certain method guidance for small sample data system evaluation in engineering test.