The data in the following table represent time study observations for a woodworking operation.
a. Based on the observations* determine the standard time for the operation, assuming an allowance of 20 percent of job times.
b. How many observations would be needed to estimate the mean time for task 1 within I percent of its true value with a 95.5-percent confidence?
c. How many observations would be needed to estimate the mean time for task 1 within .01 minute of its true value with a 95.5-percent confidence?