Using the following data and scenario, how would one calculate the standard time the manager will use to change the connectors: A large cable company received a shipment of audio-video cables with...

Using the following data and scenario, how would one calculate the standard time the manager will use to change the connectors:

A large cable company received a shipment of audio-video cables with the wrong connectors. The error was made by the cable company’s specifications provided to the overseas supplier. The operations manager calculates that it would be cheaper to manually change the connectors rather than have the supplier redo or fix the cables. The manager observes the first set of workers pulled aside to change the cables and from these observations will set a standard time. The observations are as follows for workers to each change the connectors on sets of 20 cables: 

Data from manager's work sampling: http://postimg.org/image/yscyzqy9j/

Asked on by jayson94

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Tamara K. H. | Middle School Teacher | (Level 3) Educator Emeritus

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Standard time is the time needed for the average skilled worker, "working at a normal pace," to complete any specific job ("Standard Time (Manufacturing)"). To calculate standard time correctly, we must first be sure to factor in any breaks the worker needs; therefore, standard time is easily calculated by multiplying the observed normal amount of time it takes to complete a task by the performance rating factor and then adding in any PFD allowance time plus the number one. A performance rating factor is a measure used to adjust, through observation, the amount of time it takes a skilled worker to complete a specific task at a normal pace. The performance rating factor specifically calculates the relative normal work pace during an average day based on what the observer believes should be the normal pace for such a task ("Performance Rating," McGraw-Hill Dictionary of Scientific & Technical Terms, 6th edition). When calculating how much time is needed on average to complete a task, it also becomes necessary to factor in PFD allowance time to ensure that the lost time can be made up in order to complete the task in the standard amount of time needed ("PFD Allowance"). PFD allowance time stands for "Personal needs, fatigue, and unavoidable delays allowance" ("Standard Time (Manufacturing)"). The above can be stated in the following equation:

  • Standard Time = (Observed Time)(Rating Factor)(1+PFD Allowance)

To be able to calculate the above, we must first analyze the work sampling, which means we take a large number of observations made of the workers over a drawn-out period of time and then analyze the data to derive one statistical figure based on our observations ("Work Sampling"). To analyze the work sampling, we use the two following equations, where Sp = standard error of proportion; p = percentage of idle time; q = percentage of working time; and n = number of observations:

The number of observations is also calculated using the following equation:

Calculating the above will provide you with one number for the observed time with which to plug into the equation for standard time, rather than your list of observed times, but some data seems to be missing from the file provided. You seem to be missing a percentage of idle time and a percentage of working time spent on the task out of the whole working day. However, what you do have is a performance rating factor of .95 and an allowance factor of .04. So, using the data you do have, you know the following:

Standard Time = (Observed Time)(Rating Factor)(1+PFD Allowance)
Standard Time = (Observed Time)(.95)(1+.04)
Standard Time = (Observed Time)(.95)(1.04)
Standard Time = (Observed Time)(.988)

Sources:

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