Weighing methods on the specific gravity of potato tuber for small sample.

[摘要] To weigh the specific gravity of potato tuber for the small samples by using two balances, the REIMANN's and the MOHR's, it is performed some experiments and discussions. a) In using the KAWAKAMI's improved REIMANN balance, there was no significant difference on the coefficient of variation (=C. V. ) concerned with the specific gravity of potato tuber by decreasing each sampling weight to 500gr. from 2, 500gr., but in the case that decreased to 200gr., it was obtained a very high C. V., xc.v.=8.9% in spite of the former is such xc.v.=3.2, 3.6, 4.0, 3.7 and 3.8% in each sampling weight as 2.5, 2.0, 1.5, 1.0 and 0.5kg., therefore the minimum limit of sampling weight is laid between 500gr. and 200gr. b) By the mechanical discussion of the specific gravity in relation to the scale of improved REIMANN balance and its sampling weights, I found that the result, as above mentioned, is caused from the mutual relation between the deviation in the specific gravity of tubers and the scale of this balance. The variance was approximately the same, 1.8 for between tuber size, and 1.1 for experimental error. c) So as to weigh the smaller sample weight than 500 gr., I explained the usage of the MOHR balance for weighing to the potato tuber's specific gravity, and obtained the rresult that the correlation coefficient (=r) between the MOHR's and REIMANN's balance was 0.98 and 0.87 with the confidence degree 99%.

[学科分类] 农业科学（综合）