“A picture’s worth a thousand words” may be a very cliché phrase, but that’s probably because the phrase is better understood as a picture. As Sudeshna Banerjee explains, terms like ‘hypothesis testing’ and ‘multivariate analysis’ seem off-putting even to the most seasoned IT professionals. But if quality control is assessed using the Seven Basic Tools of Quality, even those with little statistical training can apply these best practices in their everyday work affairs.
Seven Basic Tools of Quality
- Ishikawa Diagrams
- Check Sheet
- Pareto Chart
- Stratified Sampling
- Control ChartsThe Ishikawa diagram or “fishbone” diagram is a great way to get to the heart of any problem. Banerjee writes that the “5 Whys” method to Ishikawa is the best way to use this cause-and-effect visual mapping method. Then there’s the check sheet. What could be more straightforward than listing action items and then checking them off once completed?
A histogram gets a bit more sophisticated, but many professionals are familiar with this visual display style that is built into everyday software applications like Word and Excel. Going further into the histogram-style of display is the Pareto chart or 80:20 principle. Through plotting with bar and line graph, one can discern the best course of action to achieve a desired goal.
With the scatterplot, we’re getting a bit more scientific. Perhaps you want to discover the relationship between two key variables. Locating the control variable (as a line) you can plot the relationship of the second variable by noting how its instances are correlated (scattered) around the line.
With the stratification technique, one can break a population into smaller subgroups to yield a more finite and varied understanding of the data. Lastly, control charts help to measure the behavior of a given process. If the process is unstable, one can use the data from the control chart to locate the problem and formulate a solution.