Answer:
Part a) Is a positive correlation
Part b) [tex]\$69.5[/tex]
Part c) see the explanation
Step-by-step explanation:
Let
x ----> the number of items sold
y ----> the money spent on advertising
Part a) How would you characterize the relationship between money spent on advertising and items sold?
we know that
Positive correlation is a relationship between two variables in which both variables move in the same direction
so
As the value of x increases, the value of y increases
therefore
Is a positive correlation
Part b) Sally uses the function y = 1.6x + 21.5 to model the situation. What score does the model predict should be spent in advertising to sell 30 items?
we have
[tex]y=1.6x+21.5[/tex]
For x=30 items
substitute the value of x in the linear equation and solve for y
[tex]y=1.6(30)+21.5=\$69.5[/tex]
Part c) What does the number 21.5 in Part (b) mean in the context of the situation?
we have
[tex]y=1.6x+21.5[/tex]
This is a linear equation in slope intercept form
where
The slope is
[tex]m=\$1.6\ per\ item\ sold[/tex]
The y-intercept or initial value is
[tex]b=\$21.5[/tex]
therefore
In the context of the situation the number 21.5 means the initial amount spent at the begin (when the number of items sold was zero)