For the following study identify the sources of sampling bias and describe how it might affect the study and conclusion and how you might alter the sampling method to avoid the bias. A nutritionist is interested in the eating habits of college students and observes what each student who enters a dining hall between 8:00 A. M. and 8:30 A. M. chooses for breakfast on a Monday morning.

1. 1. Because convenient sampling is adopted here data is only gotten from students that eat in the hall in a given period of time so this is a source of bias

Also one study center that is the Hall of only one school is used this is also biased and may affect the result of the study

To avoid this bias a simple random sampling where each student have an equal chance of being selected in the study should be adopted

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