for question b the formula given is

ST = NTC (1+A) where:

NT = normal time

NT = t(F)(RF)

NTC = normal time for the cycle

NTC = sum of NT

for question c the formula given is

n=[(z/p)(o/t)]^2 where:

n = required sample size

p = estimation precision as a proportion of true value

t = selected time for a work item

o = standard deviation of the observed representative times for work item

z = number of normal standard deviations needed to achieve the degree of confidence desired

When conducting a time study of the Triple R Company's health insurance claims adjustment process, analyst Pablo Marmol applies the continuous method of time recording. The activity is divided into four work elements. Figure 7.3 shows the performance classification factors (RF) and the times recorded by the continuous method, r, for each work item. Process: processing for an insurance claim (Triple R Company) 1 2 2 3 Work item 1. Verify that the forms are completed and signed. 2. Write the amount of the claim, review the computations. 3. Determine the proportion of claims that would be denied. 4. Generate the letter form, enter the data for the check. t r t r t r t 0.50 0.50 0.20 0.70 0.75 1.45 1.30 Observador: Pedro Date: 05/05/05 Pica Piedra Observaciones t RF o 4 5 0.55 0.45 0.60 0.50 0.52 1.1 0.5070 3.30 5.70 8.20 10.85 0.15 0.25 0.35 0.25 0.24 1.2 0.0742 3.45 5.95 8.55 11.10 0.60 0.55 0.70 0.65 0.65 1.2 0.0791 4.05 6.50 9.25 11.75 1.20 1.10 1.10 1.30 1.20 0.9 0.1000 r 2.75 5.25 7.60 10.35 13.05 a. Calculate the normal time required for this activity. b. Calculate the standard time for this activity, assuming that the tolerance is 20% of the normal time. c. What is the appropriate sample size to estimate the time corresponding to element 2 within 10% of the true mean, with 95% confidence