I believe the answer is: double blind procedures
double blind procedures refers to a form of study in which both participants and the researchers do not know which subjects are receiving the treatment. The purpose of double blind procedures is to prevent the bias held by the experimenters along with placebo effects.
After the civil war, there was an emergence of southern farm tenancy, a system of near slavery without legal sanctions with tenant farmers in place of slaves. ... The number of farms in Texas rose from about 61,000 in 1870 to around 174,000 in 1880 and 350,000 by 1900 where farm and ranching enterprises expanded rapidly.
This most be on the worksheet or paper you received