Same error keeps appearing even when macro is changed

Wile_E_Coyote July 25, 2022, 5:29pm 2

newBranch = 0.5 * (data_a + data_b); avgBranch->Fill();

with “newer” versions of ROOT (starting with v6.14), it’s recommended to use:
newBranch = 0.5 * (data_a + data_b); avgBranch->BackFill();

BTW. After the “for” loop, you need: tree->Write();