The individuals chart (I chart) plots individual observations. The center line is an estimate of the process average. The control limits on the I chart, which are set at a distance of 3 standard deviations above and below the center line, show the amount of variation that is expected in the individual sample values.
Red points indicate observations that fail at least one of the tests for special causes and are not in control. If the same point fails multiple tests, then the point is labeled with the lowest test number to avoid cluttering the graph. If the chart shows out-of-control points, investigate those points.
Out-of-control points can influence the estimates of process parameters and prevent control limits from truly representing your process. If out-of-control points are due to special causes, then consider omitting these points from the calculations.
In these results, one observation is out of control. The process is not stable over time. When you hold the pointer over a red point, you can get more information about this point.