In: Statistics and Probability
I ONLY need answers from Question 5 to Question 10 Thank you!
After ten years on the job, Drew is trying to decide whether to go back to school and get a masters degree. He performs a cost-benefit analysis to determine whether the cost of attending school will be covered by the increase in salary he will received after he attains his degree. He does research and compiles data on annual salaries in his industry, health care, along with the years of experience for each employee and whether the employee has a master’s degree. Earning his master’s degree will require him to take out about $20,000 in student loans. He has decided that if his analysis show that the degree will increase his salary by at least $10,000, he will enroll in the program.
The data used in his analysis are the following:
Salary ($) |
Years of Experience |
Master's Degree |
Master’s Dummy |
37620 |
22 |
No |
0 |
67080 |
27 |
Yes |
1 |
31280 |
15 |
No |
0 |
21500 |
2 |
No |
0 |
75120 |
28 |
Yes |
1 |
59820 |
25 |
Yes |
1 |
40180 |
15 |
Yes |
1 |
81360 |
32 |
Yes |
1 |
35080 |
19 |
No |
0 |
36080 |
12 |
Yes |
1 |
36680 |
22 |
No |
0 |
29200 |
1 |
Yes |
1 |
33040 |
18 |
No |
0 |
30060 |
14 |
No |
0 |
53300 |
21 |
Yes |
1 |
22820 |
7 |
No |
0 |
72900 |
31 |
Yes |
1 |
55920 |
22 |
Yes |
1 |
19280 |
0 |
No |
0 |
26000 |
7 |
No |
0 |
Drew added a dummy variable to indicate whether the employee had a master’s degree. The variable “Master’s dummy” took the value 1 if the employee had a master’s degree, 0 if not. He then regressed Salary on Years of Experience and the Master’s degree dummy. What results does he find? Show in JMP or Excel.
Use the regression results to answer the following questions:
1. Write the estimated regression equation.
2. Interpret the coefficient on the variable “Years of experience.”
3. Write the estimated equation relating salary to years of experience for an employee without a master’s degree.
4. Write the estimated equation relating salary to years of experience for an employee with a master’s degree.
5. Sketch a graph illustrating your answers to questions 4 and 5 (it need not be to scale). Be sure to label the axes, slopes, and intercepts.
6. Interpret the coefficient on “Master’s Degree.” What exactly does it tell you?
7. Conduct an F-test for the overall significance of the model.
8. Conduct a t-test to determine whether there is a statistically significant relationship between years of experience and salary, holding master’s degree constant.
9. Conduct a t-test to determine whether there is strong evidence that a Master’s degree increases salary by $10,000 or more, holding years of experience constant.
10. Based on the regression results, would you recommend that Drew pursue a Master’s degree? Why or why not?
using excel>data>data analysis Regression
we have
SUMMARY OUTPUT | ||||||
Regression Statistics | ||||||
Multiple R | 0.961267 | |||||
R Square | 0.924033 | |||||
Adjusted R Square | 0.915096 | |||||
Standard Error | 5606.872 | |||||
Observations | 20 | |||||
ANOVA | ||||||
df | SS | MS | F | Significance F | ||
Regression | 2 | 6.5E+09 | 3.25E+09 | 103.3912 | 3.06E-10 | |
Residual | 17 | 5.34E+08 | 31437017 | |||
Total | 19 | 7.04E+09 | ||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | |
Intercept | 12172.34 | 2577.149 | 4.723181 | 0.000196 | 6735.032 | 17609.65 |
Years of Experience | 1362.195 | 148.436 | 9.176989 | 5.37E-08 | 1049.023 | 1675.368 |
Master's Degree | 15772.68 | 2827.306 | 5.578698 | 3.33E-05 | 9807.59 | 21737.78 |
1. the estimated regression equation is
Salary = 12172.34+1362.195*years of experience +15772.68*master's degree
2. Interpretation of the “Years of experience.” : For every one unit increase in year experience, Salary will be increased by $1362.195
SUMMARY OUTPUT | ||||||
Regression Statistics | ||||||
Multiple R | 0.88598 | |||||
R Square | 0.784961 | |||||
Adjusted R Square | 0.773015 | |||||
Standard Error | 9167.6 | |||||
Observations | 20 | |||||
ANOVA | ||||||
df | SS | MS | F | Significance F | ||
Regression | 1 | 5.52E+09 | 5.52E+09 | 65.7059 | 2.03E-07 | |
Residual | 18 | 1.51E+09 | 84044885 | |||
Total | 19 | 7.04E+09 | ||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | |
Intercept | 13554.84 | 4194.279 | 3.231746 | 0.004628 | 4742.989 | 22366.7 |
Years of Experience | 1744.774 | 215.2469 | 8.105917 | 2.03E-07 | 1292.557 | 2196.991 |
3.the estimated equation relating salary to years of experience for an employee without a master’s degree is
Salary = 13554.84+1744.774*years of experience
SUMMARY OUTPUT | ||||||
Regression Statistics | ||||||
Multiple R | 0.740067 | |||||
R Square | 0.547699 | |||||
Adjusted R Square | 0.522571 | |||||
Standard Error | 13295.71 | |||||
Observations | 20 | |||||
ANOVA | ||||||
df | SS | MS | F | Significance F | ||
Regression | 1 | 3.85E+09 | 3.85E+09 | 21.79647 | 0.000191 | |
Residual | 18 | 3.18E+09 | 1.77E+08 | |||
Total | 19 | 7.04E+09 | ||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | |
Intercept | 29336 | 4204.471 | 6.977334 | 1.62E-06 | 20502.73 | 38169.27 |
Master’s Dummy | 27760 | 5946.021 | 4.668669 | 0.000191 | 15267.87 | 40252.13 |
4. the estimated equation relating salary to years of experience for an employee with a master’s degree.
Salary = 29336+27760*master's degree