Reference: Measurement Systems Analysis: Reference Manual, Chrysler Corporation, Ford Motor Company, General Motors Company, 1995.
Program written, modified, or edited at StatSoft, Inc.}

RandomAccess;
ReDim measurements(ncases);

{Select the variable containing the measurements and input the reference value.}
if SelectVariables1('Select Variable with Measurements', 1, 1, measvar, count, 'Variable Containing Measurement Data') = 0
then stop;
if DisplayNumericInputBox('Enter Master Value for Bias Calculations', 'Master Value', refvalue) = 0 then stop;

{Compute bias and absolute bias}
for i := 1 to Ncases do
	measurements(i) := Data(i,measvar);
ValMean(measurements, 1, Ncases, meandata);
bias := meandata-refvalue;
absbias := abs(bias);

{Compute % bias relative to process variation}
EstMeth := DisplayListBox ('Choose Method to Estimate Process Variation', 'Estimate from Data|Specify Value', 1);
if EstMeth=0 then percentbiassd := missing
	else if EstMeth=1 then
		begin
		{If the process variation is estimated from the data, 6 times the standard deviation of the data will be used}
		ValStDeviation(measurements, 1, Ncases, sddata);
		percentbiassd := 100*absbias/6/sddata;
		end
	else
		begin
		{If this method is chosen, then 6 times the historical process sigma will be used for process
		 variation}
		if DisplayNumericInputBox ('Enter Process Sigma', 'Process Sigma', ProcSigma)=0
			then ProcVar := missing;
		percentbiassd := 100*absbias/6/ProcSigma;
		end;

{Compute % bias relative to tolerance width}
if DisplayNumericInputBox('Enter Tolerance Width for % Bias Calculation', 'Tolerance Width', tolerance) = 0 then
	tolerance:=missing;
percentbiastw := 100*absbias/tolerance;

{Prepare and display output}
ReDim Results(3);
Results(1) := bias;
Results(2) := percentbiassd;
Results(3) := percentbiastw;
output := NewScrollsheet(3, 1, Results, 'Results', 'Bias|% Bias Relative to Proc. Var.|% Bias Relative to Tolerance', ' ');

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