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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 | |
R_{i} | range of measurements in i^{ th} subgroup |
n_{i} | sample size of i^{ th} subgroup |
N | number of subgroups |
weighted average of subgroup means | |
z_{p} | 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 n_{i}. 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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