The following data are the monthly salaries y and the grade point averages x for students who obtained a bachelor's degree in business administration. GPA Monthly Salary ($)
2.6 3,500
3.4 3,800
3.6 4,200
3.1 3,700
3.4 4,200
3.1 2,500

The estimated regression equation for these data is = 2090.5 + 581.1x and MSE = 21,284.
Required:
a. Develop a point estimate of the starting salary for a student with a GPA of 3.0
b. Develop a 95% confidence interval for the mean starting salary for all students with a 3.0 GPA (to 2 decimals).
c. Develop a 95% prediction interval for Ryan Dailey, a student with a GPA of 3.0 (to 2 decimals).

1.) 3833.8

2.) (3428.81 ; 4238.79)

Step-by-step explanation:

1.)

Point estimate of the salary for student with GPA of 3.

Using the regression model given :

Y = 2090.5 + 581.1x

x = 3

Y = 2090.5 + 581.1(3)

= 3833.8

2.)

95% confidence interval :

Y ± Tcritical * √MSE

Y = point estimate at x =3 ; = 3833.8

MSE = 21,284

Tcritical at 95% ; df = n-2 = 6-2 = 4

Tcritical(0.025 ; 4) = 2.776

√MSE = √21284 = 145.89036

Lower boundary : 3833.8 - 2.776(145.89036) = 3428.81

Upper boundary : 3833.8 + 2.776(145.89036) = 4238.79

(3428.81 ; 4238.79)

7. d. 64

8. i. 32

9. c. 125

10. j. none of the above

11. d. 81

12. i. 216

13. e. none of the above

14. g. 240

15. e. none of the above

16. g. 32

17.   e. none of the above

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.