The correct answer is double blind study
This is a research whereby information about the experiment or test is withheld from the subjects until after the test is carried out so as to ensure that it does not influence the tester or even the participant
<span>The High Court has interpreted concepts like the First Amendment in ways that have covered both parts of social interaction. The Court has found that individual liberty to express oneself freely, worship without coercion, and to gather without recompense is to be protected, but the common good is to be promoted by also placing limits on just how far these strictures can be stretched before they become a danger to overall community well-being, such as when groups are gathering or people have made statements that are known to be inciting danger to others.</span>
The name of the largest lake in Central America is: Lake Nicaragua.
Without a lot of knowledge about black communities in the 1920's, I'd have to say it be the creation of a song genre, jazz.