So hmm notice the picture below
you're simply being asked to, approximate the area, by using 4 rectangles, like in the graph, it doesn't have to be an exact value, just an approximation, based on the width and height of the rectangles, and getting their area by that
those rectangles are 0.39 radian long, since if you split π/2 in 4 pieces, you get around that much, the last rectangle there is a bit smaller than 0.39.... but they don't have to be 4 rectangles of equal length
so, get the area of the rectangles, based on their width and height, and sum them up
Answer:
X is the GPA
Y is the Salary
Standard deviation of X is 0.4
Standard deviation of Y is 8500
E(X)=2.9
E(Y)=47200
We are given that The correlation between the two variables was r = 0.72
a)


So, slope = 15300
Intercept = 2830
So, equation : 
b) Your brother just graduated from that college with a GPA of 3.30. He tells you that based on this model the residual for his pay is -$1880. What salary is he earning?

Observed salary = Residual + predicted = -1860+53320 = 51440
c)) What proportion of the variation in salaries is explained by variation in GPA?
The proportion of the variation in salaries is explained by variation in GPA = 
Answer:
Box b
Step-by-step explanation:
Just did the quiz!