What is Work Sampling?

Explain what work sampling is and how it is used / might be used in workplace.

Work sampling is used to determine the amount of time in hours   spent on various tasks by organizational employees.  In other words, it is statistically used to find out how much time is spent on different kinds of activities. This technique is mostly used in industrial Engineering companies to estimate the amount of resources used to accomplish a given task and such resources are machines and labor

Work sampling is mostly applied in the field.  A big sampling size composed of workers is used to conducta work sampling study. For one to have accuracy in the study, random observations must be taken within that study period and should also represent all kinds of work done.  Using random observations and systematic approach, data is collected from the repeated observations of the same workers.It is then correlated with the time which has elapsed between the measurements and observations.

Write down steps in collection and analysis of work sampling data.

The following are the steps used in collecting and analyzing work sampling data.

The first procedure is to define the tasks so as the standard time can be determined. The second is to decide which task elements are to be used. These can be categorized as work being idle, absent and waiting for work. The third procedure is designing the study. Recordings and questionnaires are used to get all the information required. The fourth procedure is identifying who will conduct the sampling from the observers. After identifying the appropriate observers, begin the sampling study. Next is selecting the random visits to the organizations and collecting all the necessary information. Finally, compiling,analyzing and presenting the results after the study is complete. The analysis of the data is done using the statistical techniques. The nominal observations are then correlated between repeated outcomes. These techniques are motivated by describing the work sampling study and then comparing the results which are empirically obtained from analyses

Find the limit of accuracy achieved for each of the activities of each person, to a 95% confidence level.

John

Repairing machine

Using;

    Where, n=pq/?p²

?p= standard error of proportion

                   P= percentage of idle time

                   q= percentage of working

                    n= number of observations

=1.6

          The limit accuracy for repairing the machine is equal to 1.6

Awaiting for access permit

 =1.0

Therefore, the limiting accuracy for awaiting the access permit is 1.0

Steps in Collecting and Analyzing Work Sampling Data

Finding plant draws and information

 =0.5

The limiting accuracy for finding plant draws and information is 0.5

Not at job site

 =0.7

The limiting accuracy for not at the job site is 0.7

Awaiting supporting trades

 =0.7

The limiting accuracy for awaiting the supporting trades is 0.7

Not occupied

 =1.6

The limiting accuracy for not occupied is 1.6

Travelling

 =1.0

The limiting accuracy for travelling is 1.0

Kate

Repairing machine

 3.1

The limiting accuracy for repairing machine is 3.1

Awaiting access permit

 =1.4

The limiting accuracy for awaiting access permit is 1.4

Finding plant draws and information

 =0.6

The limiting accuracy for finding plant draws and information is 0.6

Not at the job site

 =0.4

The limiting accuracy for not at the job site is 0.4

Awaiting supporting trades

 =0.8

The limiting accuracy for awaiting supporting trades is 0.8

Not occupied

 =1.5

The limiting accuracy for not occupied is 1.5

Travelling

 =0.9

The limiting accuracy for travelling is 0.9

Paul

Repairing machine

 =3.3

The limiting accuracy for repairing machine is 3.3

Awaiting for access permit

 =1.3

The limiting accuracy for awaiting the access permit is 1.3

Finding plant drawings and information

 =0.4

The limiting accuracy for finding plant drawings and information is 0.4

Not at the job site

 =0.4

The limiting accuracy for not being at the job site is 0.4

Awaiting supporting trades

 =0.8

The limiting accuracy for awaiting supporting trades is 0.8

Not occupied

 =1.2

The limiting accuracy for not occupied is 1.2

Travelling

 =1.1

The limiting accuracy for travelling is 1.1

Eva

Repairing machine

 =2.5

The limiting accuracy for repairing machine is 2.5

Awaiting for access permit

 =1.2

The limiting accuracy for waiting for access permit is 1.2

Finding plant drawings and information

 =0.5

The limiting accuracy for finding plant drawings and information is 0.5

Not at the job site

 =0.7

The limiting accuracy for not being at the job site is 0.7

Awaiting supporting trades

 =0.7

The limiting accuracy for awaiting supporting trades is 0.7

Not occupied

 =1.4

The limiting accuracy for not occupied is 1.4

Travelling

 =1.2

The limiting accuracy for travelling is 1.2

Question 2A.3

Number of observations required;

N= Z^2pq/E^2

Where,

           E= absolute error

        P= percentage of idle

      Q= percentage of working

             Z= coefficient of the confidence level

Then;

N = (1.96^2*17.6*59.6)/0.03^2

    =4477444.4

Therefor, 4477444.4 readings are needed by John for each of the activities to be performed

Limit of Accuracy Achieved for Each Activity of Each Person

Question 2A.4

Work sampling is good based on the data since it determines the rate at which the resources like machines and workers are being used. It shows how much time is taken for the activity to be completed by the worker and also time he or she has been idle. In this case, as the manager, I would allocate the resources and time effectively to reduce idleness among workers.

Activity 2B

1. Economic order quantity is the quantity ordered by managers with an aim of reducing the ordering and holding costs per given year.  The company orders the number ofquantity to be brought with an aim of reducing the total inventory costs such as shortage costs.
2. Total annual cost= yearly holding cost + yearly ordering cost

                                            = Q/2 *C_h + A/Q*C_p+

Where, C_h= holding cost per unit

             C_p= cost to place a single order

            Q= quantity ordered

            A= demand for year

TAC = 100/2 *(60*96) +96/100*(50*96)

       =$292608

Comparing with;

Purchase cost (without discount) = total demand * cost of each unit = 96*60 = $5760

Ordering cost = number of orders per year * cost of placing each order.

For option 1, OC = 4 * 50 = $200

For option 2, OC = 1*50 = $50

Holding cost = Average inventory = 1/2 (EOQ for option 1 and 100 for option 2) * cost per holding one item * holding cost rate for option 1 and 54 unit cost for option 2 =1/2 (4 + 100) * 60 * 50 * 54 = $8424000

As a recommendation, I would recommend the company to minimize the total purchase costs since they appear to be larger than the ordering and holding costs.

Activity 2C

Cost of using the parts = $2000

Stockholding cost = 25% of 2000 = $500

Cost of stock out = $20000

Lead time = 6 months

Therefore, quantity to be held = {(2*annual demand *cost per order)/ (holding cost)}^1/2 *lead time

                                                      = {(2*96*50)/ (500)}^1/2 *6

                                                     = 26 parts should be held in store.

Activity 2D

1. Quantity per order = [2*(annual usage costs*setup costs) /annual carrying cost per unit]^1/2

                                                 = [2*(1000*75)/18.75]^1/2

                                                 =89.44 number of tyres

The quantity per order should be 89 units of tyres.  

1. Re order quantity = daily demand *lead time + safety stock

But daily demand = annual demand / number of working days = from standard deviation of daily demand = 2^2= 4

So, re order = 4*5+1000 = 1020 and reorder level = (1000/1020) *100=98.0%.

Therefore, a batch of filters should be re-ordered at the level of 98.0%

Activity 2E

Data collection tablehelps to organize the data collected into columns and rows.Data analyzing table shows how the data collected is analyzed from a table and each row corresponds to a particular record of the data.  Data recording table contains information about a single individual or item in table. Let travelling = T, Emails= E, Drawing =D, Machining =M, Cleaning =C, inspecting =I, Operating =O, programming =P, Waiting for material =W, Administration meetings =A, Planning =PL.

Question 2A.3: Number of Observations Required

From the tables below, 1- represents doing that activity and 0- not doing that activity.

Data collection table

Table1

Weeks
Activities	Mon	Tue	Wed	Thu	Fri	Sat	Sun	Mon	Tue	Wed	Thu	Fri	Sat	Sun	Sum
T	1	1	1	1	0	0	0	1	0	1	0	0	1	0
E	1	1	0	0	0	0	1	1	0	0	1	1	1	0
D	1	1	0	1	0	1	0	0	1	0	1	0	1	0
M	0	1	0	0	0	0	0	0	0	0	0	0	0	0
C	0	0	1	0	0	1	1	1	1	1	0	0	0
I		0	0	0	0	0	0	0	0	0		1	1	1
O	1	1	1	1	1	1	1	1			1	0		1
P	0	0	0	0	0	0	0	0	0	1	0	0	0	0
W		1		1		1		1	1	0	0		0
A	0	0	0	0	0	0	0	1			1	1		1
PL	1	1	1		1			1		1			1

Table2

Data recording table

Data from two weeks
Activities	Mon	Tue	Wed	Thu	Fri	Sat	Sun	Average
TE	0	1	1	1	1	1	1
D	1	1	1	1	0	0	0
M	1	1	1	1	1		1
C	0	0	0	0	0
I	1	1	1	1	1	1	1
O	0	0			0		1
P	1	1	0	0	1	0	1
W		0	0	1	1	1	0
A	1	0	1	1	0		0
PL	1	1	1	1	1	1

Data analyzing table

Table3

Activities	M	T	W	Th	Fri	Sat	Sun	Mon	Tue	Wed	Thu	Fri	Sat	Sun	Valid %	Frqu
T	1	0		1	0	1	0	1	0	1		1	0	0	1
E	1		1				1		1	1	0		1	1	0
D	1	0	0	0	1	0	0	0	0	0	0	0	0	0	0
M	0	0	1					1	1		1		1	1	0
C	0	0	1	0	0	0	0	0	0	0	0	0	0	0	0
I	0	0	0	0		1		1		1		1	0	0	0
O			1		0	0	0	0	0	0	0	0	0	1	0
P	0	0	0		1		1		1		1				0
W			1		1	0	0	0	1				1	1	0
A			1				1		0	0	0	0	0	0	0
PL	0	1		1	1	1			1			1		1	1

Time log system

Table 4

Activities	Week 1       week2	Week 1       week2	Component responsible
Working hours	Idle hours
Date               Time	Date               Time
T	Mon                2-3pm	Mon             8-1pm	A
E	Tue                 4-5pm	Tue                9-12pm	D
D	Wed                9-1pm	Wed                     4-6pm	V
M	Thu                 8-5pm	Thu                       12-6pm	E
C	Fri                   7-4pm	Fri                         8-10am	R
I	Sat                10-2pm	Sat                          9-2pm	G
O	Sun                4-6pm	Sun                       9-12pm	G
P	Mon              8-3pm	Mon                      10-3pm	E
W	Tue                1-5pm	Tue                         3-8pm	T
A	Wed              12-5pm	Wed                      6-10pm	G
PL	Thu             10-4pm	Thu                       4-11pm	B

Memo

The memo highlights the research carried out about the log time system and data collected using the work sampling technique. From week one to week two, it is significant that the log time system is important in the utilization of individual time. The study found out that, time is very well managed using the time log system unlike in situations where it is absent. In this case the time log system is significant in time utilization by the individuals. Therefore, managers are advised to come up with their own time log systems for their workers. In this case, they will appropriately follow their time log systems not waste time in other unproductive activities.

I think there is another method of getting such data, where one could use the observational method only without involving the workers. In this method, only the researcher finds out what is taking in an areawithout the individuals knowing. The method is carried out using cameras, simple recordings and eyes of the researcher. It is a good method because correct information is obtained. Here individuals do not take part in the exercise.

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