Whenever we talk about a data/sample of population, there are certain common characteristics or features that almost every data set has. There are basically three common characteristics we can find in any data. The very first feature of the data is central tendency. Every data has a tendency that they tend to cluster around some central value. Second property of the data is variation. In every data set you will find some variation, data would be scattered from each other and the last one is skewness. This data may differ in the extent of departure from some standard distribution called normal distribution.
Central Value: Central value is a single value, a single digit in the range of the data set that is used to represent the entire data set. For example: If someone asks “What is the hight of Indians”? We generally say “5/8”. That doesn’t mean that every Indian has the same height. In India we may have height of 4 feet, 5, 6 or even 7. But 5/8 is an average which represents the entire Indian height.
We have certain measures in place, by using that we can find out central tendency and interpret our data. The very common ways to measure our central tendency are mean, mode and Median. We generally use mean and median than mode.
Variation means the difference. So the difference between expected output and observed output is called variation. First property of the data is central tendency or central value. Whenever you want to study a data, first you need to know the central value of the data or we can say to find out the value wherein most of the data points are clustering around.
But central value alone can’t explain you any data set very clearly and precisely. It will give you just half information. If you want complete information then you need to include information of variation. So to measure central tendency we calculate or use mean, median or mode and if I want to calculate variation then I will have to calculate 1) Range, 2) Quartile, 3) Inter Quartile Range, 4) Variance, 5) Standard Deviation. 6) Stability Factor
Additionally, it is advisable that you also visit and subscribe Advance Innovation Group Blog (http://advanceinnovationgroup.com/blog) for more Lean Six Sigma Projects, Case Studies on Lean Six Sigma, Lean Six Sigma Videos, Lean Six Sigma Discussions, Lean Six Sigma Jobs etc.