a. Develop a correlation matrix. Which independent variable has the strongest correla- tion with the dependent variable? Does it appear there will be any problems with multicollinearity? b. Determine the regression equation. How many cars would you expect to be sold by a dealership employing 20 salespeople, purchasing 15 minutes of advertising, and located in a city?
a. Develop a correlation matrix. Which independent variable has the strongest correla- tion with the dependent variable? Does it appear there will be any problems with multicollinearity? b. Determine the regression equation. How many cars would you expect to be sold by a dealership employing 20 salespeople, purchasing 15 minutes of advertising, and located in a city?
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
Related questions
Question
![The district sales manager for a major automobile manufacturer is studying car sales.
Specifically, he would like to determine what factors affect the number of cars sold at a
dealership. To investigate, he randomly selects 12 dealers. From these dealers he obtains
the number of cars sold last month, the minutes of radio advertising purchased last month,
-the number of full-time salespeople employed in the dealership, and whether the dealer is
located in the city. The information is as follows:
Cars Sold
Last Month,
Y
127
138
159
144
139
128
Advertising,
X₁
18
15
22
23
17
16
Sales
Force,
X₂
City,
X₂
10
Yes
15
No
14
Yes
12 Yes
12
12
No
Yes
Cars Sold
Last Month,
Y
161
180
102
163
106
149
Advertising,
X₂
25
26
15
24
18
25
Sales
Force,
x₂
14
17
7
16
10
City,
X3
Yes
Yes
No
Yes
No
Yes
a. Develop a correlation matrix. Which independent variable has the strongest correla-
tion with the dependent variable? Does it appear there will be any problems with
multicollinearity?
b. Determine the regression equation. How many cars would you expect to be sold by a
dealership employing 20 salespeople, purchasing 15 minutes of advertising, and located
in a city?
c. Conduct a global test of hypothesis to determine whether any of the net regression
coefficients differ from zero. Let a = .05.
d. Conduct a test of hypothesis for the individual regression coefficients. Would you
consider deleting any of the independent variables? Let a = .05.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F7a58c08c-d66d-456a-b660-0f144d075453%2F6f1d1db8-aa24-4e9b-baae-ab2b70487fff%2Fsrpyc1i_processed.jpeg&w=3840&q=75)
Transcribed Image Text:The district sales manager for a major automobile manufacturer is studying car sales.
Specifically, he would like to determine what factors affect the number of cars sold at a
dealership. To investigate, he randomly selects 12 dealers. From these dealers he obtains
the number of cars sold last month, the minutes of radio advertising purchased last month,
-the number of full-time salespeople employed in the dealership, and whether the dealer is
located in the city. The information is as follows:
Cars Sold
Last Month,
Y
127
138
159
144
139
128
Advertising,
X₁
18
15
22
23
17
16
Sales
Force,
X₂
City,
X₂
10
Yes
15
No
14
Yes
12 Yes
12
12
No
Yes
Cars Sold
Last Month,
Y
161
180
102
163
106
149
Advertising,
X₂
25
26
15
24
18
25
Sales
Force,
x₂
14
17
7
16
10
City,
X3
Yes
Yes
No
Yes
No
Yes
a. Develop a correlation matrix. Which independent variable has the strongest correla-
tion with the dependent variable? Does it appear there will be any problems with
multicollinearity?
b. Determine the regression equation. How many cars would you expect to be sold by a
dealership employing 20 salespeople, purchasing 15 minutes of advertising, and located
in a city?
c. Conduct a global test of hypothesis to determine whether any of the net regression
coefficients differ from zero. Let a = .05.
d. Conduct a test of hypothesis for the individual regression coefficients. Would you
consider deleting any of the independent variables? Let a = .05.
![Correlations: Cars sold, Advertising, Sales Force, City
Cars sold Advertising Sales Force
-0.623
0.872
0.639
Advertising
Sales Force
City
Cell Contents: Pearson correlation
Predictor
Constant
Coef SE Coef
53.25
Advertising 0.6576
5.211
15.771
Regression Analysis: Cars sold versus Advertising, Sales Force, City
The regression equation is
Cars sold 53.2 + 0.658 Advertising + 5.21 Sales Force + 15.8 City
=
Sales Force
City
S = 8.84607
R-Sq 89.4%
P
T
12.13 4.39
0.4467 1.47
0.002
0.179
1.148 4.54 0.002
5.912 2.67 0.028
DE
Analysis of Variance
Source
SS
Regression
3 5298.6
Residual Error 8 626.0
Total
11 5924.7
0.517
0.281
Source
DE Seq SS
Advertising 1 2299.7
Sales Force 1
2442.0
City
1
556.9
R-Sq (adj) - 85.5%
MS
1766.2
78.3
0.389
F
22.57
P
0.000](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F7a58c08c-d66d-456a-b660-0f144d075453%2F6f1d1db8-aa24-4e9b-baae-ab2b70487fff%2Fcsosvul_processed.jpeg&w=3840&q=75)
Transcribed Image Text:Correlations: Cars sold, Advertising, Sales Force, City
Cars sold Advertising Sales Force
-0.623
0.872
0.639
Advertising
Sales Force
City
Cell Contents: Pearson correlation
Predictor
Constant
Coef SE Coef
53.25
Advertising 0.6576
5.211
15.771
Regression Analysis: Cars sold versus Advertising, Sales Force, City
The regression equation is
Cars sold 53.2 + 0.658 Advertising + 5.21 Sales Force + 15.8 City
=
Sales Force
City
S = 8.84607
R-Sq 89.4%
P
T
12.13 4.39
0.4467 1.47
0.002
0.179
1.148 4.54 0.002
5.912 2.67 0.028
DE
Analysis of Variance
Source
SS
Regression
3 5298.6
Residual Error 8 626.0
Total
11 5924.7
0.517
0.281
Source
DE Seq SS
Advertising 1 2299.7
Sales Force 1
2442.0
City
1
556.9
R-Sq (adj) - 85.5%
MS
1766.2
78.3
0.389
F
22.57
P
0.000
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