I have been curious if this is an effective method to prevent or resist player data changes if not made by scripts within the game. (By Table I mean Table = { })
Exploiters can access any information within a LocalScript or ModuleScript. They can't decompile anything like a ServerScript or CoreScript.
If you mean something like storing all the data in a server script in a table, that could possibly work as long as the game is FilteringEnabled and proper precautions were taken with RemoteEvents and RemoteFunctions.
If Filtering is enabled and your remotes are insecure, exploiters could easily manipulate your game without even a lick of effort.
So the answer to your question would completely rely on your scripting ability to maintain a secure game.
EDIT: To clarify though, exploiters can ONLY access memory on the local side (LocalScripts, etc.), so they cannot manipulate the table directly.