In quality management, statistical sampling and standard deviation are two key concepts.
In statistical sampling, sample size usually is determined by
Sample size = 0.25 x (certainty factor/acceptable error).
Desired certainty | Certainty factor |
95% | 1.960 |
90% | 1.645 |
80% | 1.281 |
6σ - In a normal distribution, 68.3% of the population is within 1σ. 95.45% within 2σ. 99.73% within 3σ. 99.9937% within 4σ. 99.999943% within 5σ. 99.9999998% within 6σ.
Comments
Post a Comment