The following data were obtained by observing a three-step job of a financial manager’s assistant.
a. Using the data and an allowance of 10 percent of job time, determine a standard time for the
operation.
b. Determine the number of observations that would be required to estimate the mean time for
the first element within 4 percent of the true value with a confidence of 98 percent.
c. How many observations would be needed to estimate the mean time for element C to within
.10 minute of its actual value with a confidence of 90 percent?
OBSERVATIONS (minutes per cycle)
Element
Performance
Rating 1 2 3 4 5
A 90% 1.40 1.42 1.39 1.38 1.41
B 120 2.10 2.05 2.00 1.85 1.80
C 110 1.60 1.40 1.50 1.45 1.55
