要使用控制图就要求工程师或分析员为控制图选择样本容量、抽样频率(抽样时间隔或抽样区间)和控制限。
The use of a control chart requires that the engineer or analyst select a sample size, a sampling frequency or interval between samples, and the control limits for chart.
首先分析了影响走行时间的因素，设计了推断乘客走行时间规律的抽样试验方法。
The paper focouses on the passengers' walking time on transfer pedestrians from the statistical point of view.
应用推荐