Edit/View Variables - Quality Control Tab

Quality Control Limits for a variable can be defined.  The QC Limits are used throughout OPS SQL in Time Series Graphs, Spread Reports, QC Analysis Report... 

FIELDS:

Start date: The start date for the Limit. 

UCL: Upper Control Limit.  Typically calculated as the Mean +3 Standard Deviations of the variable for a period of time when the process is determined to be in control.  99.7% of values should be below this line. 

UWL: Upper Warning Limit. Typically calculated as the Mean +2 Standard Deviations of the variable for a period of time when the process is determined to be in control.  95% of values should be below this line. 

QC Mean: Typically the target.  Is the average of values when the process is determined to be in control.

LWL: Lower Warning Limit.  Typically calculated as the Mean -2 Standard Deviations of the variable for a period of time when the process is determined to be in control.  95% of values should be above this line. 

LCL: Lower Control Limit. Typically calculated as the Mean -3 Standard Deviations of the variable for a period of time when the process is determined to be in control.  99.7% of values should be below this line. 

BUTTONS:

	Used to create a new limit.  Inserts a new row to be filled out.
	Deletes the currently selected limit or limits.

NOTES:

EXAMPLES: