Confounding . is the repetition of an experiment on more than one subject.
is a technique in which a subject doesn't know whether he or she is receiving a treatment or a placebo.
is used when subjects are assigned to different groups through a process of random selection.
occurs in an experiment when you are not able to distinguish among the effects of different factors.

2 over 5

step-by-step explanation:

the 2: 3 ratio is the length of the ac segment to the cb segment total length. this implies that the ratio between segment ac length and segment ab length is 2: 5. point c is 2/5 from a to b, so the required fraction is 2/5.

square root of 36/6 = 2.449489743

square root of 16/6 = 1.632993162

square root of 6 = 2.449489743

the answer is square root of 16/6 because the square root of 36/6 is the same answer as square root of 6 = 2.449489743