Abstract: Abstract The coefficient of variation of the raw silk size is a main quality test index in the electronic testing standard for raw silk. In order to provide rational design for the coefficient of variation of the raw silk size (CVeven and CV5m) in the electronic testing, the actual distribution needs to be known. According to the electronic test trials for 6 lots of raw silk, the frequency distributions of CVeven and CV5m are investigated, and the normal distribution fitting tests of the CVeven and CV5m were carried out by the chi-square test, and the mixed normal distribution fitting test was made by the KS statistic test method, and then the degree of fitting of this two kinds of distribution was analyzed comparatively. The results showed that the distribution of the coefficient of variation of the raw silk size could reflect the quality of the raw silk and the management level of silk reeling enterprises; the coefficient of variation of the raw silk size (CVeven and CV5m) takes the mixed distribution composed of two normal distributions.

Key words: electronic testing of raw silk, coefficient of linear density variation, fitting test of distribution, mixed normal distribution