Detection of Linear Trend from a Shewhart Chart

In the statistical process control, a primary tool to deal with slope or linear trend is the use of supplementary runs rules. Although it can be applied to any process with a linear trend, it does not estimate the rate-of-change parameter in a sample interval. In addition, the detection capability of supplementary run rule is not always great. In this paper, we propose an estimation method of the rate-of-change parameter in a sample interval which will lead to a useful detection rule for the linear trend. Some simulation results are also reported.