Installing mufflers at the Stanley Garage in Brandon, Manitoba, inwolves five work elements. Linda Stanley has timed workers performing these tasks seven times, with the results shown in the following table.

"Employee has lengthy conversations with boss $($not job related$).$

By agreement with her workers, Stanley allows a $10\%$ fatigue factor and a $10\%$ personal$-$time factor. To compute the standard time for the work operation, Stanley excludes all observations that appear to be unusual or nonrecurring. She does not want an error more than $5\%.$

a$)$ The normal time for the overall process is minutes $($round your response to two decimal places$).$

The standard time for this process is minutes $($round your response to hwo decimal places$).$

b$)$ The number of observations that are required for a $95\%$ considence level within $5\%$ accuracy is observations $($round your response to the immediate higher whiole number$).$