In the experiment of the previous exercise, the subjects were randomly assigned to the different treatments. what is the most important reason for this random assignment? (a) random assignment eliminates the effects of other variables such as stress and body weight(b) random assignment is a good way to create groups of subjects that are roughly equivalent at the beginning of the experiment(c) random assignment makes it possible to make a conclusion about all men(d) random assignment reduces the amount of variation in blood pressure(e) random assignment prevents the placebo effect form ruining the results of the study

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2.83941151 would be the answer you're looking for! : )

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12