Control Chart
carolyn celestin
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A control chart for a random variable x is a plot of observed x values in time sequence order.
1. Find the mean and standard deviation of the x distribution by
(a) using past data from a period during which the process was "in control" or
(b) using specified "target" values for mean and standard deviation
2. create a graph in which the vertical axis represents x values and the horizontal axis represents time.
3. Draw a horizontal line at height and horizontal, dashed control-limit lines
4. Plot the variable x on the graph in time sequence order. Use line segments to connect the points in time sequence order.