Quality Management Tools & Techniques Essay Example | Topics and Well Written Essays - 1250 words

Quality Management Tools & Techniques - Essay Example In addition, it is also used in the monitoring of the effects of process improvement theories. Consequently, as the standard the X-bar and R chart will only work in place of X-bar and s or the median and R chart. In order to create an X-bar and R chart you can use CHARTrunner and SQCpack software. The X-bar is used to show the mean or average of every subgroup. It also used to analyze central location. On the other hand the R-chart is used to depict how data is spread and study system variability. We can actually utilize the R charts and X-bar for any of the processes that with a subgroup size greater than one. Usually it is used when the size of the subgroup falls within two and ten. However, the s charts and X-bar charts are used those subgroups of eleven and more. The X-bar and R charts are only utilized; if you need to assess stability of the system, the data is in variable form, if the data is collected in such subgroups that are larger than one but are less than eleven. So as t o ensure the best of the results, before calculating the control limits should collect as many subgroups as possible. This is because with the small amount of data the variability of the entire system may not be represented by the X-bar and R chart. Therefore, the more subgroups utilized in the calculation of limits usually 20-25 the more reliable the results (Waite, 2010). As in the case of Scott and Larraine the utilization of 30 sub groups is actually recommended. Since Scott said that he noticed that the number of complaints seem to have significantly increased since the new system was installed, it can actually be diagnosed that the problems may be emanating from the system thus the need of checking if there is any variability in the system. But since the errors increased in the last third of the month it is also substantiated that the system has been in place close to a month. The X-bar and R charts can be of help if you commence to improve the system and later use them to ass ess the systems stability. After assessment of the system’s stability, should determine if there is need to stratify the data. This is because you may actually come across variability in the results should collect the data and enter it such way that lets you to stratify it by location, symptom, lots, time and operator. Moreover, since the hotel was continuously receiving complaints the X-bar and R charts can also be used to analyze the results of improvements of the process. This would curb down an increased trend of complaints of the inflated bills from the hotel staff. Finally, the X-bar and R charts can be used for standardization. This means the data should continue to be collected and analyzed through the process of operation. If changes have been made to the system that can make the collection of data to stop, then you can only have the perception and opinion that they improved the system (Waite, 2010). An X-bar monitors the average value of particular process overtime. This means that for every subgroup the x-bar value is plotted. The lower and upper control limits are the ones that define the range of inherent variation in the means of the subgroups when the process is in control. However, the R chart is used to monitor the process if the variable of interest is a quantitative measure. To find the upper and lower limits we use the formulae (Woodwall, 2011). UCL = ?+ 3vn and UCL ?-3vn To commence with, the R chart is