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Question 7.3: A time study of an assembly operation yielded the following ......

A time study of an assembly operation yielded the following observed times for one element of the job, for which the analyst gave a performance rating of 1.13. Using an allowance of 20 percent of job time, determine the appropriate standard time for this operation.

n = 9\quad PR = 1.13\quad A = .20

i
Observation		 Time, x
(minutes)		 i
Observation		 Time, x
(minutes)
1 1.12 6 1.18
2 1.15 7 1.14
3 1.16 8 1.14
4 1.12 9 \underline{\qquad 1.19}
5 1.15 Total 10.35
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1. \mathrm{OT}\;=\;{\frac{\Sigma{x}i}{n}}\;=\;{\frac{10.35}{9}}\;=\;1.15~\mathrm{minutes}.

2. \mathrm{NT}=\mathrm{OT}=\mathrm{PR}=1.15(1.13)=1.30\,\mathrm{minutes}.

3. \mathrm{ST}=\mathrm{NT}\times(1+A)=1.30(1.20)=1.56\,\mathrm{minutes}.

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