Answer:
Part 1) The domain of the quadratic function is the interval (-∞,∞)
Part 2) The range is the interval (-∞,1]
Step-by-step explanation:
we have

This is a quadratic equation (vertical parabola) open downward (the leading coefficient is negative)
step 1
Find the domain
The domain of a function is the set of all possible values of x
The domain of the quadratic function is the interval
(-∞,∞)
All real numbers
step 2
Find the range
The range of a function is the complete set of all possible resulting values of y, after we have substituted the domain.
we have a vertical parabola open downward
The vertex is a maximum
Let
(h,k) the vertex of the parabola
so
The range is the interval
(-∞,k]
Find the vertex

Factor -1 the leading coefficient

Complete the square


Rewrite as perfect squares

The vertex is the point (7,1)
therefore
The range is the interval
(-∞,1]
Answer:
One possible confound for the experiment is the attitude of the research assistants.
Step-by-step explanation:
A confounder simply means a variable that has impact in influencing both the dependent variable and independent variable, causing a spurious association.
So, we can conclude that the attitudes of the research assistants have positive and negative impacts in determining the reactions of both participants in the experiment.
The rudeness of a research assistant will negatively impact the response of the participant allocated to him/her.
The calmness of the other research assistant will positively impact the response of the participant allocated to him/her.
Divide 24 from both sides