Statistical Process Control-5

Distribution

  • The important distributions are –
    • Binomial Distribution
    • Poisson Distribution
    • Normal Distribution

Binomial & Poisson Distribution

  • A lot contains large number of items with a proportion of defective ‘p’ then random sample of ‘n’ items from a lot contain 0,1,2,…p…,n defectives and the probability of getting the events approximated by these distribution.
  • These are discrete distributions
  • Binomial distribution contains finite number of values
  • Poisson distribution contains infinite number of values
  • Examples : P-Chart, nP-Chart, C-Chart, U-Chart Attribute Control Charts

Normal Distribution

  • This is a continuous distribution, contains rational or irrational values
  • This distribution is categorized by two parameters
    • Average (μ)
    • Standard Deviation (σ)

y = 1/σ*2 π   ex {-(x-μ)2/2 σ2}

Examples : Average-Range Control Chart, Sigma-Range Control Chart, Moving Range Control Chart

Next:- Distribution cont..

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