| Excel Spreadsheet Templates for Quality Control, Control chart for individual observations. Monitor individual quality observations rather than samples with I-CHART.xls. In all of the control charts, the basic idea is to sample from a continuous production process at equal intervals of time and record some quality characteristic. If the process is under control, the quality characteristics should vary about the population mean in a random manner. If a sample mean falls outside the control limits, there is a very small probability that this happened due to randomness or chance alone and the process should be investigated.
The I-CHART is another variables control chart used to monitor individual observations (samples of one each) rather than larger samples. The I-CHART is most used in cases where a considerable period of time elapses between opportunities to collect quality observations. For example, there only be one quality observation per shift in operations with long lead times. Although the I-CHART is usually identified with manufacturing applications, it is widely used in casinos to monitor card, dice, and roulette games. The individual observations entered in the chart are typically the net cash profits recorded when a dealer settles his or her account with the house at the end of a work period.
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