Sales (thousands of dollars) Year Population Advertising (thousands of dollars) Previous advertising (thousands of dollars) $15713 1 102558 $20 $30 $12937 2 101792 $15 $20 $12872 3 104347 $25 $15 $16227 4 106180 $30 $25 $15388 5 106562 $15 $30 $13180 6 105209 $25 $15 $17199 7 109185 $35 $25 $20674 8 109976 $40 $35 $20350 9 110659 $20 $40 $14444 10 111844 $25 $20 Consider the model: salest = 0 + 1t + 2popt + 3advt + 4advt-1 + t where salest = sales in year t, popt = size of the population residing within 10 kilometres of the restaurant, advt = advertising expenditures in year t, and advt-1 = advertising expenditures in the previous year. Based on the sample data, a regression analysis was performed and the results are shown below. SUMMARY OUTPUT Regression Statistics Multiple R 0,994630788 R Square 0,989290405 Adjusted R Square 0,980722728 Standard Error 393,1191142 Observations 10 ANOVA df SS MS F Significance F Regression 4 71378769,21 17844692,3 115,4677605 4,12255E-05 Residual 5 772713,1899 154542,638 Total 9 72151482,4 Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Intercept 24799,62737 17008,82164 1,458045001 0,204627778 -18922,94058 68522,19531 Year 318,9594603 178,6691756 1,785195791 0,134293268 -140,3242772 778,2431977 Population -0,20186378 0,172483261 -1,17033838 0,294606217 -0,645246117 0,241518557 Advertising 134,947818 19,58889716 6,888995176 0,000986635 84,59295482 185,3026813 Previous_Advertising 295,5352939 19,53921967 15,12523524 2,2891E-05 245,3081307 345,762457 You are required to answer the following questions: Estimate the sample regression equation. What proportion of variation in annual sales is explained by variation in year, population size, advertising expenditure for current year and advertising expenditure for previous year? Construct a 99% confidence interval for From this confidence interval, can you conclude that previous year advertising expenditure influence current year sales? Test at 5% level of significance the hypothesis that year, population size, advertising expenditure for current year and advertising expenditure for previous year jointly influence annual sales.
The owner of a restaurant in Bloomington, Indianna, has recorded sales data for the past 10 years. He has also recorded data on potentially relevant variables. The following table gives data on sales and other potentially relevant variables for that particular restaurant.
Sales (thousands of dollars) |
Year |
Population |
Advertising (thousands of dollars) |
Previous advertising (thousands of dollars) |
$15713 |
1 |
102558 |
$20 |
$30 |
$12937 |
2 |
101792 |
$15 |
$20 |
$12872 |
3 |
104347 |
$25 |
$15 |
$16227 |
4 |
106180 |
$30 |
$25 |
$15388 |
5 |
106562 |
$15 |
$30 |
$13180 |
6 |
105209 |
$25 |
$15 |
$17199 |
7 |
109185 |
$35 |
$25 |
$20674 |
8 |
109976 |
$40 |
$35 |
$20350 |
9 |
110659 |
$20 |
$40 |
$14444 |
10 |
111844 |
$25 |
$20 |
Consider the model: salest = 0 + 1t + 2popt + 3advt + 4advt-1 + t
where salest = sales in year t,
popt = size of the population residing within 10 kilometres of the restaurant,
advt = advertising expenditures in year t, and
advt-1 = advertising expenditures in the previous year.
Based on the sample data, a
SUMMARY OUTPUT |
||||||
Regression Statistics |
||||||
Multiple R |
0,994630788 |
|||||
R Square |
0,989290405 |
|||||
Adjusted R Square |
0,980722728 |
|||||
Standard Error |
393,1191142 |
|||||
Observations |
10 |
|||||
ANOVA |
||||||
|
df |
SS |
MS |
F |
Significance F |
|
Regression |
4 |
71378769,21 |
17844692,3 |
115,4677605 |
4,12255E-05 |
|
Residual |
5 |
772713,1899 |
154542,638 |
|||
Total |
9 |
72151482,4 |
|
|
|
|
|
Coefficients |
Standard Error |
t Stat |
P-value |
Lower 95% |
Upper 95% |
Intercept |
24799,62737 |
17008,82164 |
1,458045001 |
0,204627778 |
-18922,94058 |
68522,19531 |
Year |
318,9594603 |
178,6691756 |
1,785195791 |
0,134293268 |
-140,3242772 |
778,2431977 |
Population |
-0,20186378 |
0,172483261 |
-1,17033838 |
0,294606217 |
-0,645246117 |
0,241518557 |
Advertising |
134,947818 |
19,58889716 |
6,888995176 |
0,000986635 |
84,59295482 |
185,3026813 |
Previous_Advertising |
295,5352939 |
19,53921967 |
15,12523524 |
2,2891E-05 |
245,3081307 |
345,762457 |
You are required to answer the following questions:
- Estimate the sample regression equation.
- What proportion of variation in annual sales is explained by variation in year, population size, advertising expenditure for current year and advertising expenditure for previous year?
- Construct a 99% confidence interval for From this confidence interval, can you conclude that previous year advertising expenditure influence current year sales?
- Test at 5% level of significance the hypothesis that year, population size, advertising expenditure for current year and advertising expenditure for previous year jointly influence annual sales.
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