Lec 11 - Stratifi

Lec 11 - Stratifi - Rational Sampling Each observation in a...

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Rational Sampling Each observation in a subgroup has the same life story Keep Sample Sizes Small new events don't occur during sampling not too expensive large enough so that X i is normally dist. large enough to detect shifts Sample Frequently don't waste money sampling every 12 hours
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Symptoms of Two Common Mistakes in Sampling Data points hug center line indicating sample averages are not normally distributed UCL LCL Data points hug control limits indicating sample averages are not normally distributed UCL LCL 2
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Stratification – Sample Averages hug center line performance measure: amount of liquid filled into a container. machine: 4 heads fill 4 containers simultaneously. each head has a slightly different mean subsample: select bottles filled by heads 1, 2, 3, 4, 5 Data points hug center line indicating sample averages are not normally distributed 3
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Stratification – Why does it happen EACH HEAD HAS A DIFFERENT MEAN! Why do points hug center line?
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This note was uploaded on 09/20/2011 for the course ENG 300 taught by Professor Albin during the Fall '11 term at Rutgers.

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Lec 11 - Stratifi - Rational Sampling Each observation in a...

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