Researchers at a car manufacturing unit are conducting a double-blind, controlled study to compare brake systems. What does double blind mean?

OPTIONS

• Only blind attendants are used.
• Special types of blinds are used.
• Samples are kept confidential from customers.
• Samples are kept confidential from testers.

ANSWER

Samples are kept confidential from testers.

EXPLANATION

Double blind experimental design means that the samples are kept confidential from testers.