How to insert fit y by x using script?

[#1]

Hello, i am doing analyze the wafer using script. But eventually, my script only work when i manual plot first fit y by x using this selection. Can i know the script that can run automatically selected fit y by x using that selection? 

Distribution(
	Continuous Distribution(
		Column( :IL_ALL_MAG_C1_S21 ),
		Normal Quantile Plot( 1 )
	),
	SendToReport(
		Dispatch(
			{"IL_ALL_MAG_C1_S21"},
			"",
			Picture Box( 5 ),
			{Set Summary Behavior( "Collapse" )}
		),
		Dispatch(
			{"IL_ALL_MAG_C1_S21"},
			"Distrib Quantile Plot",
			FrameBox,
			{Row Legend(
				IL_ALL_MAG_C1_S21,
				Color( 1 ),
				Color Theme( "Blue to Gray to Red" ),
				Marker( 0 ),
				Marker Theme( "" ),
				Continuous Scale( 0 ),
				Reverse Scale( 0 ),
				Excluded Rows( 0 )
			)}
		)
	)
);

Bivariate( Y( :Y ), X( :X ), Where( :WAFER_ID == ID_Wafer & :SITE_NO == 1 ) );

Bivariate( Y( :Y ), X( :X ), Where( :WAFER_ID == ID_Wafer & :SITE_NO == 2 ) );

[#2 · Accepted solution]

If I am understanding what you want, all you have to do is to change 

Bivariate( Y( :Y ), X( :X ), Where( :WAFER_ID == ID_Wafer & :SITE_NO == 1 ) );

Bivariate( Y( :Y ), X( :X ), Where( :WAFER_ID == ID_Wafer & :SITE_NO == 2 ) );

to

Bivariate( Y( :Y ), X( :X ), By( :WAFER_ID, :SITE_NO ) );

[#3]

Great it's work for me. Thankyou so much :))