2. Header production: The header mainly covers the following detailed information, namely, category, department, process, control item, engineering specification, sample size and frequency, in which the control item is Baidu experience page view, which is the core of the whole Xbar-R control chart production process, and the engineering specification requires a certain range of experience page views (365,438+00-380).
3. Data collection: According to the requirements, data can be collected four times a day, for example, it is divided into four time periods: 9:00, 13: 00, 17:00 and 22: 00, and the data is collected once in each time period and recorded.
After the collection is completed, calculate the maximum value, minimum value and range of four data = maximum value-minimum value, thus completing the data collection and processing part.
4. Formulation of control limits: Generally, it is necessary to provide engineering specifications and actual control at the bottom of the table, and the scope of actual control must be less than or equal to the engineering specifications. For example, the engineering specification of experience page views is (3 10-380), and the actual control can be (330-370); The engineering specification of the limit range is 70 times, and the actual limit range control can be 60 times.
5. making Xbar (average value) change trend line: Xbar change trend line includes four lines, which are the upper and lower limit of actually controlled experience page views (red straight line in the figure), median (green straight line in the figure), curve (collected experience page views data), UCL= upper limit, CL= median, LCL= lower limit, and is made by using line charts in Excel tables.
6. Production of R (extreme value range) change trend line: The R change trend line also includes four lines, namely the upper and lower limit of the actual control of extreme value range (red straight line in the figure), median value (green straight line in the figure), curve (extreme value range calculated by empirical view), UCL= upper limit, CL= median value and LCL= lower limit, which are made by line charts in Excel tables. The selection of data source is shown in the figure below.
7. Output Xbar-R control chart: Even if the whole Xbar-R control chart is completed, the changing process of experience view can be monitored, and whether the process is in a stable state can be evaluated according to the "eight criteria for judging differences", which is superior to single trend line control and is a dual control of precision and accuracy, and is widely used in enterprises.