Based on a careful work study in the Richard Dulski Corp., the results shown in the following table have been observed:

a Photocopyirig machine broken; included as delay in the allowance factor.
b Power outage; included as delay in the allowance factor.

(a) Compute the normal time for each work element.
(b) If the allowance for this type of work is 15%, what is the standard time?
(c) How many observations are needed for a 95% confidence level within 5% accuracy?

Observations (minutes) 2 3 4 5 Rating (%) Performance Element Prepare daily reports Photocopy results Label and package reports Distribute reports 35 40 33 42 39 12 10 36 15 13 4 15 18 21 17 45 120 110 90 85 3 3 5 5