Answer:
1. single sample design
2. matched pairs
3. two independent samples.
Step-by-step explanation:
the response variable is known as the dependent variable, it is the variable that the researcher is interested i finding. the response variable is the x variable that responds to changes in the independent variable.
1.
In this question the researcher has only one sample that is the specimen. that is the reference specimen that she obtained. Therefore it is a single sample design.
the response variable here is the measurement of concentration.
2. In this question we have two pairs, men and women. The researcher is interested in comparing attitudes as she interviews them. so response variable is attitude or behavior
3. this is a 2 independent sample design. The researcher is using two different methods to test and their average is being compared.
By definition, we have

So, we have to solve two different equations, depending of the possible range for the variable. We have to remember about these ranges when we decide to accept or discard the solutions:
Suppose that 
In this case, the absolute value doesn't do anything: the equation is

We are supposing
, so we can accept this solution.
Now, suppose that
. Now the sign of the expression is flipped by the absolute value, and the equation becomes

Again, the solution is coherent with the assumption, so we can accept this value as well.
Since a pound of sugar increases proportionally to the total cost of sugar bought, then the function can be written as:
c(p) = 0.42p
Where: c(p) = total cost of sugar bought
p = pounds of sugar
c(p) is a function of p, because c(p) depends on p.
Answer:
15.51
Step-by-step explanation:
14.91x4%=.60
14.91+.60=15.51
It’s c. Where the two planes intersect