~んがため(に)/~んがための      => in order to ~ N1
ため => In order to, for N4
Purpose, target
ため(に) => For, because… N4
Cause and Effect
めったな => hardly; rarely; seldom N2
Ban
めったにない => Rarely N3
Degree. Level, Amount
あらためる => to revise; to replace N3
Happens next
めったに~ない => hardly; rarely; seldom N3
そのため => Because of A, B N3
Reason, Result, Response
そのため(に) => hence; for that reason; because of ~ N3
んがため => For the purpose of doing A N1
Reason, Result, Response
ひとつには…ためである => Partly because of ... N3
Cause, reason
~ためしに…てみる => to attempt, to test, to try out N1
Invite and advise