Control Charts

Control Charts

1. Used to graphically plot either attribute data or variable data as averages or individuals to determine if a process is int statistical control

2. Types of control charts

   • Variable (Continuous)
     • X-R Chart(average value and range(
       • Used for controlling and analyzing a process using continuous values of product quality such as length or concentration
     • x Chart(individual, mesuared value)
       • if process datais obtained over extended time intervals of if sub-grouping of data is not effective
   • Attribute(Discrete)
     • np Chart (Numberof defective units)
     • pChart (Fraction defective)
       • used whe quality characteristic is simbolized by number or defective units or fractions defective bad appliances
     • cChart(Number of defects)
       • used for monitoring and analyzing a process by number or product defects scratches on drywall, defective lathe joints or uneven kitchen counter tiles
     • u Chart (Number of defects per units)