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We can apply Six Sigma Concepts in delivering high quality Manufactured Items or Processes in a Software organization. As the title says we have to understand statistics and apply it to the manufactured part or a Software Product or a Process.
In a Statistical Study the word "population" refers to the entire set of items under discussion. For example the population might be the set of parts shipped to customer B last Friday. It is typically not feasible to measure a characteristic on each item in a population therefore a statistical study will randomly select a sample from the population, measure each item in the sample and analyse the resulting data. The analysis of sample data produces statistics. Example of Sample statistics include sample mean, sample median, sample standard deviation.
Suppose a population consists of the numbers 2, 3 and 4 the dot plot diagram for this population would be a straight line.
Statistics is a field of mathematics that pertains to data analysis. Statistical methods and equations can be applied to a data set in order to analyse and interpret results, explain variations in the data, or predict future data. A few examples of statistical information we can calculate are:
Standard Deviation can be calculated as follows to calculate the variance follow these steps: Work out the Mean (the simple average of the numbers) Then for each number: subtract the Mean and square the result (the squared difference). Then work out the average of those squared differences
Below is the Sample Distribution of the mean of the 3 Numbers 2, 3 and 4.
|
Sample |
Sample Mean |
|
2,2 |
2.0 i.e.= (2+2)/2 |
|
2,3 |
2.5 |
|
2,4 |
3.0 |
|
3,2 |
2.5 |
|
3,3 |
3.0 |
|
3,4 |
3.5 |
|
4,2 |
3.0 |
|
4,3 |
3.5 |
|
4,4 |
4.0 |
|
Total |
27.0 |
|
Mean |
3.0 |
|
Standard Deviation of Sample Means |
0.816 |
Therefore the Central Limit theorem holds good which states that regardless of the shape of the population, the sampling distribution of the mean is approximately normal if the sample size is sufficiently large. The approximation improves as the sample size gets larger.
Finally the statistical approach can be used to improve the quality of the manufactured item in a factory, software product or a organization process where we can apply the basic statistics and other tools of six sigma like FMEA and Risk Abatement Plan.
The Author Suresh V. Menon is a Subject Matter Expert on ERP and has worked in various capacities as Project Manager, Test Manager, and Implementation Manager & Principal Consultant and can be contacted at testconsultants@outlook.com for comments and queries.
