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XCHART Statement |
The following notation is used in this section:
process mean (expected value of the population of measurements) | |
process standard deviation (standard deviation of the population of measurements) | |
mean of measurements in i th subgroup | |
Ri | range of measurements in i th subgroup |
ni | sample size of i th subgroup |
N | number of subgroups |
weighted average of subgroup means | |
zp | 100p th percentile of the standard normal distribution |
The following table provides the formulas for the limits:
Table 42.22: Limits for ChartsControl Limits |
LCL = lower limit |
UCL = upper limit |
Probability Limits |
LCL = lower limit |
UCL = upper limit |
Note that the limits vary with ni. If standard values and are available for and , respectively, replace with and with in Table 42.22.
You can specify parameters for the limits as follows:
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