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 15 percent of job time.

b. How many observations would be needed to estimate the mean time for element 2 within 1 percent of its true value with a 95.5 percent confidence?

c. How many observations would be needed to estimate the mean time for element 2 within

.01 minute of its true value with a 95.5 percent confidence?

OBSERVATIONS (minutes per cycle)

Element Performance Rating 1 2 3 4 5 6 1 110% 1.20 1.17 1.16 1.22 1.24 1.15 2 115 0.83 0.87 0.78 0.82 0.85 1.32*

3 105 0.58 0.53 0.52 0.59 0.60 0.54

*Unusual delay, disregard time.

 LO.1