Unit two

Unit two

1. Histograms

   • To determine the spread or variation of a set of data points

2. Control Charts

   • One of the goal on using a control chad is to achieve and maintain process stability
     • Why use?
       • To monitor process variation
     • Common causes
       • This variation is expected and predictable

3. "P" Charts

   • Are used to measure the proportion of items in a sample that are defectives
     • Ucl=p+Zσp
       • Lcl=p-Zσp
         • P
           • Sample of proportion defective
       • Z
         • Number of standard deviations
       • σp
         • Standar deviation of sample
       • σp=√((P(1-p))/n)

4. "C" charts

   • Are used to monitor the quantity of defects per united
     • UCL
       • C +Zσc
     • LCL
       • C-Zσc
     • σc
       • √c

5. Variable data charts

   • Elapsed time
   • Temperature
   • Radiation dose

6. “X” BAR AND “R” CHARTS

   • x
     • Media
       • UCL=D4 R
         • LCL=D3*R
   • R
     • Rango
       • UCL=X+A2 R
         • LCL=X-A2*R

7. THE 7 QC STATISTICAL TOOLS

   • Pareto charts
   • Cause and effect diagram
   • Graphs
   • Check sheet
   • Histograms
   • Scatter diagrams
   • Control charts

8. Fihbone

   • components
     • Straight line
     • Ribs
     • Medium size bones
     • Small bone

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