3 ms·

This fallacy is known as "pseudoreplication": the erroneous belief that multiple samples (or a long measurement) of dependent data (i.e. the same person year af

This fallacy is known as "pseudoreplication": the erroneous belief that multiple samples (or a long measurement) of dependent data (i.e. the same person year after year) is equivalent to getting many independent samples. If you measure the same two people year after year, you just measure their genetic predispositions and personal habits more and more precisely. You cannot distinguish them from the results of your coffee/tea intervention. http://www.statisticsdonewrong.com/pseudoreplication.html http://www.statisticsdonewrong.com/pseudoreplication.html

rodionos 11y ago
In case of caffeine addiction tests, I would argue that a life-long trial of fewer people over a short-term trial of many people would produce more statistically significant results because the impact is accumulative over a long period of time. Consider asbestos or even smoking. Compare the results of 10 lifelong smokers vs 1000 smokers who tried it just once. Anyways, did you read the article on wikipedia? The prisoners were twins and their rations was the same - 3 intakes per day.
- capnrefsmmat 11y ago
  The goal of a trial is to eliminate other possible explanations for the phenomenon in question. You take a large sample, and randomly assign people to groups, so all the idiosyncratic variations average out. With only one person per group, you can't eliminate many possible reasons for their differing life spans: one may have caught a disease the other was not exposed to, they may have had different nutrition, different amounts of exercise, different habits, a zillion other things. After all, do other twins die at exactly the same time? No. They die years apart for many other reasons. Unless this twin experiment could eliminate all those possible reasons, it shows us nothing about coffee specifically.

3 ms·

This fallacy is known as "pseudoreplication": the erroneous belief that multiple samples (or a long measurement) of dependent data (i.e. the same person year af

by capnrefsmmat 11y ago

rodionos 11y ago
In case of caffeine addiction tests, I would argue that a life-long trial of fewer people over a short-term trial of many people would produce more statistically significant results because the impact is accumulative over a long period of time. Consider asbestos or even smoking. Compare the results of 10 lifelong smokers vs 1000 smokers who tried it just once. Anyways, did you read the article on wikipedia? The prisoners were twins and their rations was the same - 3 intakes per day.
- capnrefsmmat 11y ago
  The goal of a trial is to eliminate other possible explanations for the phenomenon in question. You take a large sample, and randomly assign people to groups, so all the idiosyncratic variations average out. With only one person per group, you can't eliminate many possible reasons for their differing life spans: one may have caught a disease the other was not exposed to, they may have had different nutrition, different amounts of exercise, different habits, a zillion other things. After all, do other twins die at exactly the same time? No. They die years apart for many other reasons. Unless this twin experiment could eliminate all those possible reasons, it shows us nothing about coffee specifically.