Received: 3 February 2020
Accepted: 13 May 2020
First Online: 11 June 2020
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: Ethics approval for the study from which the current data were taken was obtained from an independent scientific advisory board overseeing the original data collection and from the school authorities of the participating federal states in Germany.
: Informed parental consent was obtained for all participants.