Children not attending a private, full-time, day school and who are being instructed in study and recitation for at least three hours a day for 175 days each calendar year by a private tutor or other person in the several branches of study required to be taught in the public schools of this state and in the English language shall be exempted. The tutor or other person shall hold a valid state credential for the grade taught. The instruction shall be offered between the hours of 8 o'clock a.m. and 4 o'clock p.m.