Statistics applied to Quality Control

Statistics applied to Quality Control

1. Histograms Cause and Effect Diagrams

   • First used by Ishikawa in the 1940s, they are used to identify the underlying symptoms of a problem or "effect" as a means to find the root cause

2. Control charts

   • In statistical process control are tools used to determine whether or not a manufacturing or business process is in a state of statistical control.

3. The check sheet

   • Is a simple document that is used for collecting data in real-time and at the location where the data is generated. Data is read by observing the location and number of marks on the sheet. 5 Basic types of Check Sheets:
     • Classification
     • Location
     • Frequency
     • Measurement Scale
     • Check List

4. Pareto chart

   • Named after Vilfredo Pareto, is a type of chart that contains both bars and a line graph, where individual values are represented in descending order by bars, and the cumulative total is represented by the line.

5. scatter plot

   • Is a type of mathematical diagram using Cartesian coordinates to display values for two variables for a set of data.

6. Stratified sampling

   • Is a method of sampling from a population. When populations vary, it is advantageous to sample each subpopulation (stratum) independently.

7. The Deming Cycle

   • The concept of PDCA is based on the scientific method, as developed from the work of Francis Bacon (Novum Organum, 1620)
   • The scientific method can be written as "hypothesis"–"experiment"–"evaluation" or plan, do and check.