Abstract：According to the synthetic process of the indirect measurement uncertainty of the national standard, the formula for calculating the uncertainty of the cylinder volume calculated from the measured values of the diameter and height of the bottom surface is derived. The degree of freedom calculated of the volume of the cylinder with derived formula less a relevant item about indication error of the micrometer in the denominator in the formula of degrees of freedom than Error Theory and Data Processing (6th Edition) edited by Fei Yetai. After analysis, the indication error of the micrometer is a random error in measuring height and diameter of the cylinder, it is not relevant. Therefore, in calculating the degree of freedom of the cylinder volume uncertainty, the relevant items on indication error of the micrometer should not be introduced to the calculation formula of degree of freedom of uncertainty.
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