A Statistical Analysis of the Stone Arrow Heads Buried in the Grave Pits of Jomon Period.

Abstract

In this article, the authors intended to prove statistically that the stone arrow heads which were buried in grave pits had been selected from those used in daily life, and/or intentionally made for grave goods (funerary objects).The materials used were stone arrow heads unearthed from a grave pit and from other areas in the same site. The site belongs to the latest Jomon period, and is located at Satsukari in the southern part of Hokkaido. The excavation was undertaken by the members of the Historical Museum of Hokkaido during the period of 1971 through 73.The investigation was carried out using a variance analysis method to prove whether the variances of measurements of the stone arrow heads differed between those excavated from the grave pit (Group 1) and from the other areas of the site (Group 2). The numbers of materials were 57 for Group 1 and 62 for Group 2.The measurements made were maximum length (F in figure 2), maximum breadth (C), maximum thickness, apex length (D), base length (E), and weight, the line through the middle of the arrow head in figure 2 being the reference line.The test of difference in means showed that the significant differences were recognized in only two measurements, maximum length and apex length, and in both cases Group 2 showed smaller mean values than the Group 1. This fact appears to prove that the arrow heads in Group 2 were worn out by daily use. In contrast to this, insignificant differences between Groups 1 and 2 might show that the arrow heads of both groups belonged to the same population.On the other hand, the variance analysis showed that the variances for all the measurements were larger in Group 2 than in Group 1. The results apparently show that the arrow heads from the grave pit might have been selected intentionally on the basis of a certain standard.Thus, it may be safely emphasized that the statistical analysis on the stone arrow heads from the Satsukari site in Hokkaido proved intentional selection of those buried in the grave pits. In addition, it is very probable that the people of the site used relatively new artifacts when they prayed for a departed soul.