A new manager bounce is so common that it's actually more of a surprise when they don't win.
It's a combination of the old crap manager no longer being there, players that were out of favour finally getting a chance, and players who were previously lazy bastards suddenly making some effort for fear of being transfer-listed.
It's all utterly meaningless until they meet strong opposition or do it consistently over a season, and even then it's still not a sign of anything long term - as we've seen time and again with new managers who get a tune out of their team for a while and then it all unravels.
Apparently Carrick 'steadied the ship' and Ragnick 'has already made an impression'. Well, they said exactly the same thing about Solskjaer.