The time required to get an oil change at a quick change service shop is normally distributed with a mean of11.6 minutes with a standard deviation of 2.7 minutes. Over the course ofa day. 53 customers come into the service shop for an oil change. a) Recalculate the standard deviation in order to apply the central limit theorem. [:] Round your answer to 4 decimal places. b) Find the probability that the average time to change the oil for these 53 customers is less than 12 minutes. PO?"