Most clinical trials I see have a fixed sample size.  In some cases they have prior data that allows estimating the effect size and the variance or distribution of values, and calculate the sample size from that for a certain power.  In other cases it is just a guess.

Why wouldn't people run a clinical trial in which the sample size was determined during the trial?  (for example, by increasing it until the confidence interval narrowed to a certain size specified in advance)  Is there any reason this would not be a valid design?  Are there any examples of trials like that, and any references for designing a trial like that?


Question: How to set the ID3 Year on an mp3?
Answer: Try the KDE MP3 ID3 tag editor.

With the KDE MP3 ID3 tag editor, you can edit tags of multiple files, e.g. the artist, album, year and genre of all files of an album typically have the same values and can be set together.UA

To install, just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command(s) below:

sudo apt-get install kid3


Or just click KDE MP3 ID3 tag editor