% drop below 200 day moving average for a buy signal

Is there a “standard” % drop below the 200 day moving average that is often used as a buy signal for an equity? For mid to long term trading.

I have a new watch list I'm using that has a 200 day moving average %. I didn't know if 10% below is a safe buy signal, 20%, etc. or if there is an industry standard?

Same thing for a sell signal.