Abstract
In order to establish the quality assurance system of fruits by means of sampling inspection theory, factors affecting sugar content (Brix) of Kaki (Dyospyros Kaki L cv. Fuyu) were analized by Hayasi's quantification scaling type 1, and then, the sampling inspection plans were designed. The results were as follows:
1. The factors that had a remarkable influence on the sugar content were tree and producer in order of degree. Therefore, the sampling unit was expected to be stratified by these factors.
2. Every population variance of the sugar contents of fruits on a tree, a producer or producers was estimated respectively as following:
That was, in the early season, 1.241, 1.459, 2.224; in the best season, 0.805, 1.205, 2.915; in the late season, 0.885, 1.798, 3.471.
3. It was considered that the distribution of sugar contents of fruits on a tree was approximately the normal distribution by plotting on the normal probability paper. That resulted the distribution within trees or producers in the normality nearly if the fruits were sampled from a random tree. So, it would be of good that Single sampling inspection or Sepuential sampling inspection was applied.
4. If the sampling lot was made of fruits from a tree in the best season, the quality assurance was able to do as follows:
When the sample size was five and the lower acceptance value was 16.23 by means of Single sampling inspection, it was able to assure the buyer that the mixing percentage of fruits 14.0 and below (fraction defective) was 0.1% and below with the probability of 90%. That was equivalent to assuring of the mean value of the lot 16.77 and over.
If Sequential sampling inspection was adopted, the same assurance as Single sampling inspection was able to do when the lower acceptance value 17.86 at one sample, 17.05 at two, 16.77 at three and so forth.
