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Spotfire Statistica | - |
This example shows how you can create a multiple stream X-bar and R chart. A special case of multivariate control charting occurs when there are multiple data streams from identical independent processes. For example, a manufacturer may run multiple identical production lines with identical machines. In that case, the data can be considered multiple independent data streams, and special quality control charts can be constructed to monitor the extremes (highs, lows) across the multiple streams. When a particular stream is responsible for a large number of consecutively observed extreme values (across all streams), then it is likely that a quality problem has occurred or is developing with the respective process associated with that data stream.
For the purpose of this example,we will use a subset of MultipleStreams.sta dataset that ships with Statistica. To open this a user may click on Open>>Open Examples>>Datasets>>MultipleStream.staThe data contains measurements from a machine that fills 10 eight-ounce bottles of juice at a time. Each spigot on the machine is considered a data source or data stream, thus the Multiple Stream Process (MSP) has 10 streams. When the process is in-control, the amount of juice in a bottle will be 8 ounces, regardless of which spigot filled the bottle.