Answer:
To remove the bias
Step-by-step explanation:
The study in which neither the subject nor the experimenter knows which subject is receiving a particular treatment is known as double blind study.
In the given study, the treatment is caffeine pills. So neither the subjects know they received caffeine pills nor the experimenter knows that which subject received which pill. Hence, this is a double blind study.
Such a study is used to remove the potential bias from the study. For example, if a subject is told that he is given a caffeine pill his actions will re-enforce that he has taken the pill, even in the case when he is given a placebo instead of actual pill. So the belief of the subject may cause bias in the result. This is removed by using the double blind study.
Also, since the experimenter also does not know which subject received the treatment, they won't act in different ways towards different subjects to give away any hints or clue. If the experimenter knows which subjects is given actual treatment, he may behave differently with him. So the double blind study removes this sort of bias as we..
Answer:
Difference between the distances traveled by Mary and Kate = 226 feet
Step-by-step explanation:
By applying Pythagoras theorem in right ΔDEF,
(DE)² + (EF)² = (DF)²
By substituting DE = 264 feet and EF = 900 feet
(264)² + (900)² = (DF)²
DF = √(69696+810000)
= √879696
= 937.92
Distance traveled by Kate diagonally = 938 feet
Distance traveled by Mary = DE + EF
= 264 + 900
= 1164 feet
Difference between the distances traveled by Mary and Kate = DF - (DE + EF)
= 1164 - 937.92
= 226.07
≈ 226 feet

means that the triangles are congruent, that is exactly identical.
The order of letters is very important. Form the given congruence we can write the following ratio:

(notice that we do not mix the order: the first 2 letters of VWX are compared to the first 2 letters of KLJ and so on)
the ratio is one because the corresponding sides are equal.


Answer: 5 units