unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TfrmHillSlopeRegr = class(TForm)
  private
    procedure mmuFileOpenClick(Sender: TObject);
  public
    { Public declarations }
  end;

var
  frmHillSlopeRegr: TfrmHillSlopeRegr;
  // to make the OutputFile variable be visible out of scope of this unit,
  // declare it in the interface section
  OutputFile: TStringList;

implementation

{$R *.dfm}

uses
  AnalysisOptions;

procedure TfrmHillSlopeRegr.mmuFileOpenClick(Sender: TObject);
begin
  // whatever code here
end;

// these must be at the end of the unit not enclosed by begin..end blocks
initialization
  OutputFile := TStringList.Create;
finalization
  OutPutFile.Free;

end.