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John, being a Statistician is part of my Job. I am certified by the ASQ (American Society of Quality). I understand exactly what they did and the mistakes they made. To get to 95% confidence with the data they collected, they had to open the confidence interval wide. And even then, they did not collect the information to check against other population norms to make sure they had a representative sample, or to check if they are double counting.
Cluster sampling is used to minimize the work by the samplers. 47 data points are not exactly exhaustive.
What would be the best way to confirm this study? Do another sample with 50 other clusters. A 2 sample T test will easily tell if the samples are the same or different.
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James
The pessimist complains about the wind; the optimist expects it to change; the engineer adjusts the sails.- William Arthur Ward (1921-1994)
Red-beard for President, 2020
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