Timeline for At least, how many times an experiment should be replicated?
Current License: CC BY-SA 2.5
9 events
| when toggle format | what | by | license | comment | |
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| Feb 7, 2011 at 11:51 | vote | accept | Manuel Ramón | ||
| Nov 12, 2010 at 12:32 | comment | added | Manuel Ramón | I totally agree with you. We can not decide to stop an experiment because the results are what we wanted or otherwise continue. In my work usually replicate experiments 3 to 5 times depending on the availability of time. I think 3 replicas are sufficient. Also, if the estimates are accompanied by a measure of variability (standard errors and confidence intervals) the reader will have enough information to decide whether these estimates are more or less "reliable". | |
| Nov 9, 2010 at 21:25 | comment | added | csgillespie | @Manuel: This is a very dangerous strategy and you need to be careful. You can't just carry out a few experiments and stop when you like. Basically you can't change the sample size midway through your experiment unless you are very careful. | |
| Nov 9, 2010 at 5:19 | vote | accept | Manuel Ramón | ||
| Nov 9, 2010 at 5:19 | |||||
| Nov 9, 2010 at 5:19 | vote | accept | Manuel Ramón | ||
| Nov 9, 2010 at 5:19 | |||||
| Nov 8, 2010 at 13:39 | comment | added | Manuel Ramón | So, the idea could be to replicate the experiment two or three times, evaluate the variability of the estimates and based on this variability decide whether more replicates will be necesary. | |
| Nov 8, 2010 at 13:30 | comment | added | whuber♦ | @Manuel You are correct; you need to assess individual variability. The number of repeated measurements needed depends on the size of that variability, how the variability translates to uncertainty in the inferences about the population, the cost of repeating the measurements, practical constraints such as the time needed for replication, and (perhaps) technical issues like the possibility of positive temporal correlation among the replicate measurements. | |
| Nov 8, 2010 at 12:56 | comment | added | Manuel Ramón | The size of population is important, for sure. Thus, for the blood pressure example three individuals may be unrepresentative. My case is different, there is no a problem of sample size. Imagine you have a sample of fixed size (it is not possible to include more individuals) and you want to assess the effects of a drug on blood pressure. Would you realize the experiment only once or several times? I think that it should be replicated at least two (or three) times in order to consider the individual variability of each subject. | |
| Nov 8, 2010 at 12:07 | history | answered | csgillespie | CC BY-SA 2.5 |