How do we conduct a double-blind investigation?

Question

How do we conduct a double-blind investigation?

Answer 1

If you are having a control group and a real group (such as placebo and real drug) you need to make sure that the testers/ analysts and statisticians do not know what group is which.

Answer 2

'Double-blind' means that neither the person taking the test or the person giving the test knows the right answer.

Answer 3

A double blind investigation means neither the people being experimented on - NOR the people doing the experiment know whats going on - which means niether can subconciously (or diliberately) influence the outcome.

For example - you are testing a new drung on medical volunteers. Some get placebo - and some get the real thing.

A single blind would be where the nurses administer the drug - but don't tell the patients which one they have. But then the nurses might treat the ones who got the real drug better - and their healing would have nothing to do with the medicen.

The double blind would be where a porter (or whoever) sorts the drugs & placebos into two groups and hands them to the nurses - but doesn't tell them which one is which untill after the experiment is over.