Chapter 7, Problem 3P

a)

Summary Introduction

To determine: The average cycle time for each operation.

Introduction: The amount of the dependency on human effort by an organization in terms of achieving its goals is given by the work design. It is directly linked to the productivity of an organization where good work design helps in achieving high productivity.

Explanation of Solution

Given information:

		Observation (minutes per cycle)
Element	Performance rating	1	2	3	4	5	6
1	90	0.44	0.5	0.43	0.45	0.48	0.46
2	85	1.5	1.54	1.47	1.51	1.49	1.52
3	110	0.84	0.89	0.77	0.83	0.85	0.8
4	100	1.1	1.14	1.08	1.2	1.16	1.26

Calculation of average time per cycle:

	Observation (minutes per cycle)
Performance rating	1	2	3	4	5	6	Average time per cycle
90	0.44	0.5	0.43	0.45	0.48	0.46	0.46
85	1.5	1.54	1.47	1.51	1.49	1.52	1.505
110	0.84	0.89	0.77	0.83	0.85	0.8	0.83
100	1.1	1.14	1.08	1.2	1.16	1.26	1.156667

Excel worksheet:

Average time per cycle is calculated by taking average of all cycle in each element which is average of 0.44, 0.5, 0.43, 0.45, 0.48 and 0.46 which gives 0.46 as average time per cycle for element 1 and similar method follows for element 2, 3 and 4.

b)

Summary Introduction

To determine: The normal time for the operation.

Explanation of Solution

Given information:

		Observation (minutes per cycle)
Element	Performance rating	1	2	3	4	5	6
1	90	0.44	0.5	0.43	0.45	0.48	0.46
2	85	1.5	1.54	1.47	1.51	1.49	1.52
3	110	0.84	0.89	0.77	0.83	0.85	0.8
4	100	1.1	1.14	1.08	1.2	1.16	1.26

Formula:

$\begin{array}{lll}\text{NT}\hfill & \text{=}\hfill & \text{Observed}\text{time × Perform}\text{Rating}\hfill \\ \hfill & \text{=}\hfill & \text{OR × PR}\hfill \end{array}$

Calculation of normal time:

		Observation (minutes per cycle)
Element	Performance rating	1	2	3	4	5	6	Average time per cycle	NT
1	0.9	0.44	0.5	0.43	0.45	0.48	0.46	0.46	0.414
2	0.85	1.5	1.54	1.47	1.51	1.49	1.52	1.505	1.27925
3	1.1	0.84	0.89	0.77	0.83	0.85	0.8	0.83	0.913
4	1	1.1	1.14	1.08	1.2	1.16	1.26	1.156666667	1.156667

Excel worksheet:

Normal time is calculated by multiplying observed timing, 0.46 and performance rating, 0.9 which yields 0.414 minutes for element 1, 2, 3 and 4.

c)

Summary Introduction

To determine: The standard time for the operation.

Explanation of Solution

Given information:

		Observation (minutes per cycle)
Element	Performance rating	1	2	3	4	5	6
1	90	0.44	0.5	0.43	0.45	0.48	0.46
2	85	1.5	1.54	1.47	1.51	1.49	1.52
3	110	0.84	0.89	0.77	0.83	0.85	0.8
4	100	1.1	1.14	1.08	1.2	1.16	1.26

Formula:

$\begin{array}{lll}\text{Standard time}\hfill & \text{=}\hfill & \text{Normal time × Allowance factor}\hfill \\ \hfill & \text{=}\hfill & \text{NT × AF}\hfill \end{array}$

Calculation of standard time:

$\begin{array}{lll}{\text{AF}}_{\text{job}}\hfill & =\hfill & 1+\text{A}\hfill \\ \hfill & =\hfill & 1+0.15\hfill \\ \hfill & =\hfill & 1.15\hfill \end{array}$

Allowance factor is calculated by dividing 1 with difference of 1 and 0.15 which yields 1.15.

		Observation (minutes per cycle)
Element	Performance rating	1	2	3	4	5	6	Average time per cycle	NT	Afjob	ST
1	0.9	0.44	0.5	0.43	0.45	0.48	0.46	0.46	0.414	1.15	0.4761
2	0.85	1.5	1.54	1.47	1.51	1.49	1.52	1.505	1.27925	1.15	1.471138
3	1.1	0.84	0.89	0.77	0.83	0.85	0.8	0.83	0.913	1.15	1.04995
4	1	1.1	1.14	1.08	1.2	1.16	1.26	1.157	1.157	1.15	1.330167

Excel worksheet:

Standard time for the operation is calculated by multiplying normal time of 0.414 minutes with allowance factor of 1.15 which gives 0.4761 minutes for element 1 and same procedure goes with element 2, 3 and 4.