An Outlier In The Confidence Interval
In today's department meeting, I had shared this phenomenon happened in my demo materials for our India customer. An outlier in the figure is showed as a small red triangle. The blue line just above the outlier is the upper historical limit. That represents that the outlier is in the historical interval. The historical interval is like as what we know about the confidence interval. The historical interval is for a fitted values of the model and has its confidence level 95%. The outlier happened in the historical interval. There is a little bit conflict with my statistical sense. As our common sense, an outlier is the data out of the range what we expect. At the same time, about the range what we expect, we in general use the confidence interval to represent. Intuitively, an outlier would be out of the interval. But, in practice, why it is in it? Numerically, the outlier is detected by the software because its fi...