Originally Posted By: oil_film_movies
Originally Posted By: Popsy
Except if the labs don't know what oil they are analyzing ?
Right, so this a blind study, not "double".
It would be double if the person mailing the sample out to the labs didn't know what oil they were mailing, which would be ridiculous & useless in this experiment. Scientists only use "double" blind methods when the person giving a treatment or drug or conducting the experiment could possibly introduce bias, and in this case, just mailing in a sample doesn't introduce any bias.
The person analyzing the data should be blinded should not know what oil is which to eliminate any bias. They should analyze the data blindly and a 3rd disinterested party should unblind the study after all the data is analayzed. Well, that's how we roll with drug studies. Maybe this study doesn't require such a strenuous level of unbias.
The 3rd party has a secret key. A=Mobil 1, B=PYB, etc. The labs and data cruncher only know A, B, C...