PS 8
Business Statistics
Problem Set # 8
Due Monday December 1st
1. You have data on three variables for college graduates: years of work experience, student GPA and monthly salary after graduation in $. You collect data from 6 students.
Student
Years of Work Experience
GPA
Monthly Salary ($)
1
3
2.6
3300
2
0
3.4
3600
3
4
3.6
4000
4
1
3.2
3500
5
2
3.5
3900
6
5
2.9
3600
Following are the regression results for the data using Excel. In this problem, you will be interpreting the regression results. (For Practice, you may want to see if you can replicate these results using the data above in Excel.) (7 Points)
a. Write the estimated regression equation.
b. Interpret the coefficient of GPA.
c. Interpret the coefficient of Years of Work Experience.
d. Which variables have a statistically significant relationship with the dependent variable at the 5% level?
e. Which variables have a statistically significant relationship with the dependent variable at the 1% level?
f. What is the 95% confidence interval estimate for the coefficient of GPA?
g. What is the 90% confidence interval estimate for the coefficient of Years of work experience?
2. The owner of Showtime Movie Theaters would like to estimate weekly gross revenue as a function of advertising expenditures. Historical data for a sample of eight weeks are as below:
Week
Weekly gross revenue ($1000s)
TV Advertising ($1000s)
Newspaper Advertising ($1000s)
1
96
5.0
1.5
2
90
2.0
2.0
3
95
4.0
1.5
4
92
2.5
2.5
5
95
3.0
3.3
6
94
3.5
2.3
7
94
2.5
4.2
8
94
3.0
2.5
Following are the regression results for the data using Excel. In this problem, you will be interpreting the regression results. (For Practice, you may want to see if you can replicate these results using the data above in Excel.) (8 Points)
a. Write the estimated regression equation.
b. Interpret the coefficient of TV Advertising.
c. Interpret the coefficient of Newspaper Advertising.
d. What is the estimate of
Problem Set # 8
Due Monday December 1st
1. You have data on three variables for college graduates: years of work experience, student GPA and monthly salary after graduation in $. You collect data from 6 students.
Student
Years of Work Experience
GPA
Monthly Salary ($)
1
3
2.6
3300
2
0
3.4
3600
3
4
3.6
4000
4
1
3.2
3500
5
2
3.5
3900
6
5
2.9
3600
Following are the regression results for the data using Excel. In this problem, you will be interpreting the regression results. (For Practice, you may want to see if you can replicate these results using the data above in Excel.) (7 Points)
a. Write the estimated regression equation.
b. Interpret the coefficient of GPA.
c. Interpret the coefficient of Years of Work Experience.
d. Which variables have a statistically significant relationship with the dependent variable at the 5% level?
e. Which variables have a statistically significant relationship with the dependent variable at the 1% level?
f. What is the 95% confidence interval estimate for the coefficient of GPA?
g. What is the 90% confidence interval estimate for the coefficient of Years of work experience?
2. The owner of Showtime Movie Theaters would like to estimate weekly gross revenue as a function of advertising expenditures. Historical data for a sample of eight weeks are as below:
Week
Weekly gross revenue ($1000s)
TV Advertising ($1000s)
Newspaper Advertising ($1000s)
1
96
5.0
1.5
2
90
2.0
2.0
3
95
4.0
1.5
4
92
2.5
2.5
5
95
3.0
3.3
6
94
3.5
2.3
7
94
2.5
4.2
8
94
3.0
2.5
Following are the regression results for the data using Excel. In this problem, you will be interpreting the regression results. (For Practice, you may want to see if you can replicate these results using the data above in Excel.) (8 Points)
a. Write the estimated regression equation.
b. Interpret the coefficient of TV Advertising.
c. Interpret the coefficient of Newspaper Advertising.
d. What is the estimate of