diff --git a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas
index 5dbe11cd1..6eecee104 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas
+++ b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas
@@ -96,7 +96,7 @@ begin
     exit;
   end;
 
-  xCol := OS3MainFrm.DataGrid.Rows[0].IndexOf(Trim(XEdit.Text));
+  xCol := GetVariableIndex(OS3MainFrm.DataGrid, Trim(XEdit.Text));
   if xCol = -1 then
   begin
     ErrorMsg('X variable not found.');
@@ -104,14 +104,14 @@ begin
   end;
 
   nY := YBox.Items.Count;
-  SetLength(selected, nY + 1);  // one more for the x column, needed by Correlations()
+  NoSelected := nY + 1;   // one more for the x column, needed by Correlations()
+  SetLength(selected, NoSelected);
   for j := 0 to nY - 1 do
-    selected[j] := OS3MainFrm.DataGrid.Rows[0].IndexOf(YBox.Items[j]);
-  selected[nY] := xCol;
-  NoSelected := nY + 1;
+    selected[j] := GetVariableIndex(OS3MainFrm.DataGrid, YBox.Items[j]);
+  selected[nY] := xCol;   // This goes into the extra element of "selected"
 
-  SetLength(RowLabels, NoVariables);
-  SetLength(ColLabels, NoVariables);
+  SetLength(RowLabels, NoSelected);
+  SetLength(ColLabels, NoSelected);
   for i := 0 to NoSelected-1 do
   begin
     RowLabels[i] := Trim(OS3MainFrm.DataGrid.Cells[selected[i],0]);