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Trying to Create XmR Trend Control Charts in Excel?

QI Macros can create them for you!

Use an XmR Trend Control Chart to evaluate stability of processes using trended data - costs (e.g., inflation).

XmR Trend Control Chart created using QI Macros for Excel.

The Chart will calculate the fit of the data to the trend:

Useful Fit R² > 0.80
Ryx = 0.991
Slope = 3.649
Sigma = 4.265
Probability = 0.444

• R² gives the fit of the line to the trend. Greater than 0.80 is a good fit.
• Ryx is the linear correlation coefficient. Compare to probability for df = n - 2.
• Slope is the positive or negative slope of the trend
• Sigma is the estimated standard deviation Rbar/d2
• Probability is critical value for Ryx. If Ryx > Probability then a statistically significant correlation exists.

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