|Activity Sampling |A technique in which a large random sample of snap observations is taken over a period of time of a group | |(also known as Work |of machines, processes or workers. | |Sampling) |Each observation records what is happening at that instant of time randomly picked. The percentage of | | |observations recorded for a particular activity or delay is a measure of the percentage of the time during| | |which that activity or delay occurs in the work situation. | | |The primary task of the technique is to identify and compare the productive and non-productive activities | | |to the total study time period. | |Rated Activity Sampling|An extension of activity sampling to obtain the standard time by providing rating and allowance | | |percentages. | |Applications |In industries where large numbers of similar machines and workers engaged on similar tasks are employed. | |Underlying Principle |The theory of activity sampling is based on the laws of probability and binomial distribution. The concept| | |is that the characteristics of a large enough, yet unbiased sample chosen at random would be | | |representative of the population characteristics. |
|Reasons why activity sampling is preferred to time study: | |1 |An activity sampling study can be interrupted or temporarily delayed at any time without affecting the results. | |2 |One observer can collect data concerning simultaneous activities of a group of men, machines, or both. In fact, many | | |activity sampling studies may be conducted at the same time by one observer. | |3 |The observer does not need to be a trained Industrial Engineering personnel, unless the purpose of the study is to | | |determine a time standard. | |4 |It is cheaper in terms of manpower and the time taken. | |5 |It is easier to do counts than make measurements of time. No timing device is required. | |6 |The time it takes to make an observation depends on what is being observed. (Often, only a glance is needed to | | |determine the activity.) | |7 |Work of a long cycle time may be studied with fewer observer hours. | |8 |The duration of the study is longer, which minimizes effects of short-period variations. | |9 |As activity sampling needs only instantaneous observations, the operator has less chance to influence the findings by| | |changing his or her work method. | |10 |There is little or no disruption of work. | |11 |It is well suited for non-repetitive tasks. |
|Disadvantages of Activity Sampling | |1...
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