By measuring the sound levels (leq) 8 hours during 08:00-16:30 from September-November, 2558 (2015) by random sample in each store, for example, the 4 month time in education.
By measuring the volume (leq) 8 hours during 08: 00-16: 30 hrs. From September - November 2558 month by random sampling in each sample point per month, four times the area of study.
The measured noise (Leq) 8 hours during the 08: 00-16: 30. Since September to November 2558 by random samples in each sample point per month 4 times in the area studied.