Conducting the Knowledge Transfer
February 12, 2025
The automobile industry all over the world is facing an unexpected challenge. Diesel vehicles which were the star performers in many countries across the world are now rapidly losing market share. Diesel vehicles are being shun by regulators and consumers alike. This has caused problems for many automobile companies around the world. For instance, Jaguar […]
Why Do Silicon Valley and Bangalore Score over Regions and Cities? Silicon Valley in California State in the United States and Bangalore in India, as well as Shanghai in China, are known to be hotspots of innovation wherein they attract the best talent and the most number of startups as well as entrepreneurs compared to […]
Time and Material Billing Time and material billing refers to the billing process wherein actual number of hours worked and the resources deployed are billed on an as is basis with the margin added to it. In other words, time and material billing refers to the billing that is done as per the actual number […]
Internet Technology has impacted our day to day life beyond imagination. It has changed the way we make purchase decisions, the process by which we compare products and finally buy the product. All this has been enabled instantly by the click of a mouse, sitting in the comfortable environs of your home. Lets take the […]
The crash in the value of the Turkish lira is not really a surprise. President Erdogan has been following loose monetary policies despite receiving warnings from several monetary experts. In a way, this economic turmoil has been self-inflicted. Turkey has increased its money supply to about 300% in the past seven years! The rationale behind […]
Just like there are many types of discrete data charts available, there are also many types of continuous control charts available. The Six Sigma process methodology prescribes which chart must be used when. The prescription in the case of continuous data points is largely based on sample size.
Below is the list of the different control charts that need to be used for different sample sizes:
Individual Chart: In the case of an individual data chart, each observation is plotted as a separate data point. This means that there is no rational subgrouping of data. This chart must therefore be used when the sample size equals 1.
Moving Range Charts: Unlike the individual data chart, the moving range chart plots the difference between two data consecutive points. The sample size of this type of control chart is therefore 2. Here the rational subgrouping of data points is based on whether they are consecutive. The moving range data charts therefore have one less data point as compared to the individual charts.
X Bar R Chart: The X bar and R chart are used to control a process when the sample size is small and constant. This is because in small sample sizes, the range of the sample approximates the standard deviation, which would be pointless to calculate, given the small size.
The X bar and R Chart are actually two different charts, which need to be looked in tandem to understand the behaviour of a process. The X bar chart shows the average performance of the process. The R chart which plots the difference between the smallest and largest value explains the variability of the process.
X Bar S Chart: The X bar and S charts are used when the sample size used to conduct the study is large and/or variable. As in the case of X bar and R chart, X bar and S charts too have a number of values. The X bar chart ensures that the mean of the process is in control whereas the S chart monitors the standard deviation. When used in tandem, they help monitor the performance of a very large process with relative ease.
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