Received: 8 July 2018
Accepted: 21 August 2018
First Online: 25 August 2018
Compliance with ethical standards
: The research related to human use complied with all the relevant national regulations, institutional policies, and was in accordance with the tenets of the Helsinki Declaration. The study protocol was approved by the Ethical Committee of Poltava V. G. Korolenko National Pedagogical University, Poltava, Ukraine. The Ethical Comitee consented in writing to the study.During realization of tests, all participants provided informed consent and used all measures for maintaining anonymity of participants.
: Respondents give written informed consent to publish the study results anonymously.
: The authors declare that they have no competing interests.