QUANTITATIVE TOOLS

QUANTITATIVE TOOLS

1. CONTROL GRAPH

   • tool used to distinguish variations
     • random variations
       • are repeated casually
     • variations due to assignable causes or special
       • identify, investigate and bring under control
   • What is it for?
     • Evaluate the stability of a process Determine process settings Confirm improvement of a process
   • types of graphics
     • length or thickness of an element. measure the quality characteristic. more sensitive and confirms possible quality problems even before they are already relevant.
     • Attribute control chart Defective Units Nonconforming or conforming product They allow to classify as acceptable or unacceptable a product

2. PARETO CHART

   • graphical technique to identify the most important problems and determine in which order to solve them, quantitative comparison
     • When it's used?
       • When you want to analyze the quality of a product or service
         • • line above the bars represents the accumulated magnitude of the defects
           • vertical left is in number of rejected products and vertical right in percentage of characteristics

3. HISTOGRAM

   • are graphs that indicate the frequency of a fact through a distribution of the data.
     • what is it used?
       • Interpret the variations of the data. Provide a better view of the information provided by the data to interpret it more appropriately. Identify the causes of the problem. Check the causes. Evaluate the solution once the cause of the problem has been eliminated.

4. DISPERSION DIAGRAM

   • mathematical diagram that uses the Cartesian coordinates to show the values of two variables for a data set. allows to study the relations between two associated sets of data that appear in pairs
     • What is a scatter diagram used for?
       • Two factors or causes related to quality. Two quality problems. A quality problem and its possible cause
         • CORRELATION
           • Correlation is no more than how both variables are related to each other

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