LazStats: Refactor ResistanceLineUnit, use report-and-chart template form.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@7755 8e941d3f-bd1b-0410-a28a-d453659cc2b4

applications/lazstats/source/units/mathunit.pas

@@ -51,11 +51,14 @@ procedure Calc_MeanVarStdDev(const AData: DblDyneVec; out AMean, AVariance, AStd
 procedure Calc_MeanVarStdDevSS(const AData: DblDyneVec; out AMean, AVariance, AStdDev, ASumOfSquares: Double);
 procedure Calc_SumSS(const AData: DblDyneVec; out Sum, SS: Double);
 
+function Calc_Median(const AData: DblDyneVec): Double;
+
 
 implementation
 
 uses
-  Math;
+  Math,
+  Utils;
 
 // Calculates the error function
 //                              /x
@@ -572,6 +575,21 @@ begin
 end;
 
 
+function Calc_Median(const AData: DblDyneVec): Double;
+var
+  N, midPt: integer;
+begin
+  SortOnX(AData);
+
+  N := Length(AData);
+  midPt := N div 2;
+  if odd(N) then
+    Result := AData[midPt]                          // odd no. of values
+  else
+    Result := (AData[midPt-1] + AData[midPt]) / 2;  // even no. of values
+end;
+
+
 initialization
   InitFactLn();