Answer:
Q1
slope=0.16
intercept=30.2
Q2
78.2
Q3
36%
Step-by-step explanation:
Question 1
We are given that
xbar=280
sx=30
ybar=75
sy=8
r=0.6
The regression line can be written as
y=a+bx
a=intercept
b=slope
where
and
b=0.6*(8/30)
b=0.16
a=75-0.16*280
a=30.2
Thus,
slope=0.16
intercept=30.2
Question 2
The regression line in the given scenario
y=30.2+0.16x
Julie pre exam total before the exam was 300.
y=30.2+0.16*300
y=30.2+48=78.2
So, the predicted final exam score of Julie is 78.2.
Question 3
R² denotes the variation in dependent variable y explained by the linear relationship of x and y.
R²=0.6²=0.36
Thus, the proportion of the variation in final exam scores that is explained by the linear relationship between pre-exam scores and final exam scores is 36%.