Yasir wants to determine if there is a relationship between room color and sleep. based on his research, yasir makes an educated guess that people fall asleep more quickly in a room painted blue than in a room painted yellow. he asks several people which color they like better -yellow or blue- and uses their responses to determine if his educated guess was correct. what is missing from yasir’s scientific investigation? a testable hypothesis that is based on research an experiment that directly tests the hypothesis variables to be tested by an experiment research on the topic to see what others have learned

Yasir wanted to study the relationship between sleep and room color. So he has done all the background study required on the topic and arrived at a hypothesis that people fall asleep more rapidly in a room painted in blue color than in a room painted yellow. Yasir inquired several people which color they like better -yellow or blue- and used their feedback to decide whether his hypothesis was correct. There was no experiment conducted to observe the effect of a room color on sleep and the variables to be tested in the experiment were not properly identified.

Therefore, the correct answer would be,

An experiment that directly tests the hypothesis

Variables to be tested by an experiment