Abstract Reporting descriptive statistics requires rounding the results. Experienced researchers typically round the numbers to one or two decimals, following the APA manual. However, this general recommendation ignores the sample size and the instrument’s precision. Herein, expressions are derived that indicate how many decimals are reliable and so at what point the results should be rounded. The derivations are based on the measurement precision, that is, the precision of the raw data and uses propagation of error techniques. Two scenarios are considered, one in which systematic measurement error is possible and one in which only non-systematic measurement error is assumed. An example is provided showing how to round means, standard deviations and t values, among others, and an R library is available to automatize calculations.

中文翻译：

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几位小数？基于测量精度的四舍五入描述性和推理性统计

Abstract 报告描述性统计需要对结果进行四舍五入。经验丰富的研究人员通常按照 APA 手册将数字四舍五入到一位或两位小数。然而，这个一般性建议忽略了样本量和仪器的精度。在这里，导出的表达式表明有多少小数是可靠的，因此结果应该在什么点四舍五入。推导基于测量精度，即原始数据的精度，并使用误差传播技术。考虑了两种情况，一种是可能出现系统测量误差的情况，另一种情况是假设只有非系统测量误差。提供了一个示例，展示了如何舍入均值、标准差和 t 值等，并且可以使用 R 库来自动化计算。