When measuring Young's modulus by polished rod method, progressive difference method, drawing method and least square method are usually used for data processing.

When measuring some physical quantities with unclear functional relations, the drawing method is often used. The data points are discrete, and the final curve should be smooth (continuous), so that the curve has the meaning of "average". In scientific research, professional function drawing software such as Origin is often used for drawing. The drawing method is intuitive and convenient, and can be interpolated and extrapolated.

When two physical quantities meet the proportional relationship in the experiment, or a research object changes periodically with the experimental conditions and records that the research object reaches a certain condition (such as peak value, fixed phase, etc.). ) and then use interpolation method to improve data utilization and reduce random error.

In short, the two have different uses, and no one is more accurate than anyone else.