During a regular workday, a worker is exposed to the following noise levels: 70 dBA for 2.5 hours, 95 dBA for 1 hours, 90 dBA for 0.5 hour, and 85 dBA for 4 hours. i. Calculate the permissible exposure time for each of the four noise exposure intensities. ii. Calculate the total noise dose. iii. Calculate the time-weighted average for the combined noise exposures. iv. Is this exposure within the permissible exposure level set by OSHA (1983)?