Installing mufflers at the O'Sullivan Garage in Golden, Colorado, involves five work elements. Jill O'Sullivan has timed workers performing these tasks seven times, with the results shown in the following table. Observation (minutes) 3 4 5 1 2 7 6 4 4 Element Select correct muffler Remove old muffler Weld/install new muffler Check/inspect work Complete paperwork Performance Rating 110% 90% 105% 100% 130% 4 6 15 5 8 14 4 7 14 24 8 6 12 6 15* 6 16 3 7 13 18* 7 4 5 15 4 7 3 5 6 6 *Employee has lengthy conversations with boss (not job related). By agreement with her workers, Jill allows a 10% fatigue factor and a 10% personal-time factor. To compute the standard time for the work operation, Jill excludes all observations that appear to be unusual or nonrecurring. She does not want an error more than 5%. The normal time for the overall process = 38.09 minutes (round your response to two decimal places). a) The standard time for this process = 47.51 minutes (round your response to two decimal places). 95% confidence level within 5% accuracy = observations (round your response to the immediate higher whole b) The number of observations that are required for number)