 Hello friends, after studying the introduction to the work sampling and the procedure for the work sampling, now let us go a step ahead. We will study applications of work sampling with a suitable example and we will also find out by numerical that how many observations are required for a given accuracy level and for the given confidence level. The outcome of the today's session will be, you will be able to make work sampling studies to the appropriate situations. The applications part we will study further discuss something about how to find out the sample size and with a small example we will discuss about what is and how to find out the number of samples required for the given accuracy and confidence level. The applications of work sampling are it is a very simple technique which can be used in wide variety of situations such as manufacturing, servicing, office operations and some of the other circumstances like manufacturing we want to study the utilization of a machine, utilization of equipment, utilization of a resource like a CMM or in some service sector like we are going to have a store operation and what is utilization of the store. We want to apply this in a bank in a hospital in variety of areas we can apply this particular sampling process and where we would like to find out what are the total governing factors which are utilizing what is the non utilization portion of the particular resource. It can also be used not only for resource it can be also used for the finding out utilization of a person also if I am operating a particular machine what is the utilization of the operator and what is the utilization of the machine that also can be studied by the focusing on the work sampling study. Once we take work sampling study it generally can be analyzed in terms of delays there are variety of delays which are occurring in a process avoidable delay and unavoidable delay. Unavoidable delays may be because of a particular situation where probably things are beyond a control like electricity failures and so on and where are avoidable delays where which are in the process design or in the management system or policies or practices or procedures and then on the basis of this we can establish find out the standard time record for the job. We also can have the work sampling study for variety of analysis of job activities on the part of supervisor engineer inspector office personnel etc. It also can give utilization of the machine for example a crane is there and it is observed that crane is continuously hold up by a particular operator or particular resource or a machine and then there is demand for other crane. By sampling study we will be able to find out what is the utilization and what is the delay in the crane whether really it is calling for additional crane or we can have a better process measurement and then we can have redesign of the process so that the crane same can be utilized. In the heavy forklift trucks the metal hand equipment also a problem of bottlenecks in some of the companies where you will find that entire forklift or all metal hand equipment from warehouse to warehouse are generally bottlenecking and there is a complaint always that we want additional metal handling resources in that case we should study that sampling process and then find out what is utilization of the various equipments and then think of additional equipments which based on the economy and the analysis of the work sampling study. It also can be used for comparing the efficiencies of the two departments. Suppose there is one department other department utilization of one and other department the utilization is having the x and y and what are the efficiencies of this by taking sampling study of each department we will be able to compare the efficient method. To provide more equitable distribution of work in a group in a group activity in a teamwork this issue generally is observed so that we have to have proper utilization and distribution of the work. Work sampling will try to give this equal distribution as such. Job evaluation we want to have job descriptions and we want to have job evaluation variety of methods work sampling will help to analyze and define correctly the job evaluation of the particular job. For appraisal of safety performance again sampling can be used for organizational efficiency can also since utilization and efficiency are related to each other higher is utilization higher is the efficiency so therefore organizational efficiency generally we are discussing about what is the plant efficiency plant efficient 60 percent 80 percent that means we are saying that around 20 to 40 percent of unutilization or inefficiency is there we can find out where this inefficiency levels are and then how to reduce the inefficiency time and increase the efficiency to a higher level to determine the nature and extent of cycles and peak load variations in observed activity. This is one more area where we find work sampling to be very effective and useful where there is a cyclic variation of peak load and offload activities we want to balance the resource may be man material or machine and then get the even load distribution in that case we can study the sampling out of peak hours and then the lean hours and try to balance the peak and lean hours as such. So, once you understand the applications of work sampling we should be able to define where can I use work sampling and where cannot I cannot use the work sampling for example I am a CNC operator and I want to find out the time required for a particular job well time study being a suitable method of work measurement rather than work sampling, but there are 10 CNC machines and 10 operators in a machine shop and then I want to find out what is the utilization of the entire CNC shop then I can go for work sampling method I can have 10 CNC machines at a time I can have one observer who can take random observations at variety of the same machines on a regular intervals the intervals are again calculated by random number generations and then you will mark on working non-working of each of the machine. Suppose there are 100 observations are there and 10 machines are there total 1000 observations will be there and out of the 1000 suppose 800 observations are observed to be working we come to the conclusion that 80% is the utilization of the entire CNC shop it is not please remember that it is not giving utilization of a single machine at in isolation it is giving the total utilization it may happen that one machine may be utilized 100% one may be utilized at 60% and still the sampling will show you 80% as the total utilization of the entire machine shop after the applications of work sampling the crucial factor in the work sampling is determination of sample size accuracy of the sampling it depends on the three factors one is sample size the accuracy level required and the confidence level required for the particular job how do we determine the sample size here is the formula it is the formula for determining sample size is given by PS is equal to X sigma P which is equal to X into P into bracket 1 minus P upon N where we will find that X is the value which depends upon the desired confidence level where to get this desired confidence level this is available from normal distribution 6 sigma kerm where it is have ranging from 10% to 95% 98% generally for all our sampling studies we are taking 95% as a confidence level and for 95% confidence level where to find out what is the value of the X by referring to the particular sigma kerm then P is the percentage occurrence of the activity it may be working non-working breakdown and so on as error in the fraction that is the desired accuracy level and N number of observations required let us practice this with a small problem with a small numerical the numerical is like this suppose that we have to assume a confidence level of 95% and desired accuracy level is 5% we have to determine number of observations required for the study the work sample method is to be used to determine the utilization of a group of drilling machines the preliminary study indicates that the machines are utilized for about 60% of the time try to understand the problem first before going for the solution of this already it is a group of drilling machines suppose there are 20 drilling machines and with a preliminary observation of 100 we have come to take on that hundred and twenty two thousand observations we have done it out of that 200 we have found that 1200 observations we are having working as such as a result of that in the preliminary study we have come to the conclusion that 60% of the utilization and based on this preliminary study now we want to go for a detailed work sampling study with a confidence level of 95% and with a accuracy of 5% so three figures are required for determining the sample size one is the confidence level the accuracy required and the present utilization of with a pilot study more is the confidence level or lesser is the higher is the accuracy level of course the number of observations definitely will go on increasing how to solve this problem think of this let us go back to our formula and then try to fill all these figures from this problem where s is the desired relative accuracy desired relative accuracy that is 5% which is 0.05 p is the percentage occurrence of the activity which is coming from the pilot study pilot study has shown 60% as the utilization therefore we are taking p as 0.6 x 2 from 95% confidence level now how this 2 has come you have to go for 6 sigma level 6 sigma graph where we have to find out 95% confidence level you will find the 95% confidence we will come at 2 sigma therefore 2 is the figure for after that n are the number of observations which you have to find out then substitute all these values and then find out number of observations that is 0.05 which is accuracy level 60% of the utilization from the pilot study and then p into 1 minus p upon n where n is to be found out and then we are substituting all this formula and then calculate the result that is the final number of observations are 1067 that is 1067 observations are required for the particular desired confidence level of 95% and with accuracy of 5% what is the meaning of this the meaning is that if I take 1067 observations and then I calculate sampling study definitely I will my study will show an accuracy of 95% with a confidence level of 95% so and these 1067 observations are to be taken at random intervals random intervals are to be taken from the random number table generations okay this is the in summary where we have calculated the sample size and in the entire session today we have found out what are the various applications how to select a sampling technique depending upon the situation and then before the filing study we have to take pilot study take observations find out the utilization decide the accuracy level and confidence level fill the data in the formula and then find out the total number of observations required then start the real study of work sampling thanks thank you