Again Captain Davenport consulted McCoy and the chart
Consider the chart in exhibit 1, below, which compares soaring Sales (the blue line) with ebbing Operating income (the pink line).
To illustrate we'll create a chart with the underlying spreadsheet data shown in exhibit 2, below.
Most SPC software programs only have median chart factors for sample sizes up to 10, which limits their use for higher-cavitation molds, according to van der Veen.
Evaluation using the M/I chart revealed two things: changes in median weights indicated global shifts in the process; and the weight for cavity number six was consistently lower than all of the others.
The R chart is a plot of the range, or the difference between the highest and lowest values you found when you measured each of your samples--again, against time.
The data from which the chart was made is included, and shows the kind of data sheet to use.
Chart 10: PREPAID/WHOLESALE SUBSCRIBERS BY OPERATOR
Chart 11: PREPAID/WHOLESALE SUBSCRIBER GROWTH BY OPERATOR
To create this chart, enter the data shown in columns A through D; then enter the following formulas:
You can, of course, substitute any Wingdings character you like for the n in the formulas to produce a different image in the chart.
With the assistance of the [X-bar] chart, an otherwise unseen problem was detected and eliminated.
The R chart shows the daily range of values compared to the UCL and average lines.
21: MONTHLY ARPU GROWTH BY OPERATOR (YoY %) --
113: CAPEX BY OPERATOR (REPORTING CURRENCY) --