TL;DR
Manchester United has excelled offensively under Michael Carrick, leading the league in shot conversion rate and scoring significantly more goals than expected. However, concerns arise about the sustainability of this performance as the team has only ranked 9th in expected goals created.
Manchester United's attack has been running blisteringly hot under Michael Carrick, which is obviously fantastic in the short term, but slightly worrying for the future when it inevitably cools down.
Eight teams have been better at creating chances based on expected goals since Carrick took charge at Old Trafford, but having the best shot conversion rate in the league means United have scored seven more goals than a team historically would from the chances they've had - more than any other side.
Looking at attack and defence overall, the only side to have overperformed their xG numbers by more than United in this time are Nottingham Forest, who are enjoying their own "new manager bounce" under Vitor Pereira.

[BBC]
Of the six players who've been the most clinical in the Premier League since Carrick took over in mid-January, three of them play for his team.
Only Forest's Morgan Gibbs-White has been more ruthless with his finishing than Matheus Cunha, while Benjamin Sesko and Casemiro have also been enjoying a hot spell in front of goal recently.