In: Statistics and Probability
Health Care Corporation (HCC) sells medical supplies to hospitals, clinics, and physician’s offices. HCC currently markets in three geographic regions of the U.S.: The South, the West, and the Midwest. These regions are divided into many smaller sales territories. HCC’s management is concerned about the effectiveness of a new bonus program. Management wants to know if the bonus paid in the past year was related to the sales. In determining this relationship, they also want to take into account the advertisement expenditure. The data set is below. In this data set, the variables are:
SALES = sales (in thousands of dollars)
ADV = amount spent on advertising in each territory (in hundreds of
dollars)
BONUS = total amount of bonus paid in each territory (in hundreds
of dollars)
REGION is a variable coded to represent the geographic region as
follows: REGION = 1 if South; = 2 if West; = 3 if
Midwest
SALES | ADV | BONUS | REGION |
963.50 | 374.27 | 230.98 | 1 |
893.00 | 408.50 | 236.28 | 1 |
1057.25 | 414.31 | 271.57 | 1 |
1183.25 | 448.42 | 291.20 | 2 |
1419.50 | 517.88 | 282.17 | 3 |
1547.75 | 637.60 | 321.16 | 3 |
1580.00 | 635.72 | 294.32 | 3 |
1071.50 | 446.86 | 305.69 | 1 |
1078.25 | 489.59 | 238.41 | 1 |
1122.50 | 500.56 | 271.38 | 2 |
1304.75 | 484.18 | 332.64 | 3 |
1552.25 | 618.07 | 261.80 | 3 |
1040.00 | 453.39 | 235.63 | 1 |
1045.25 | 440.86 | 249.68 | 2 |
1102.25 | 487.79 | 232.99 | 2 |
1225.25 | 537.67 | 272.20 | 2 |
1508.00 | 612.21 | 266.64 | 3 |
1564.25 | 601.46 | 277.44 | 3 |
1634.75 | 585.10 | 312.35 | 3 |
1159.25 | 524.56 | 292.87 | 1 |
1202.75 | 535.17 | 268.27 | 2 |
1294.25 | 486.03 | 309.85 | 2 |
1467.50 | 540.17 | 291.03 | 3 |
1583.75 | 583.85 | 289.29 | 3 |
1124.75 | 499.15 | 272.55 | 2 |
Conduct a Multiple Regression.
4. Provide a clear-mathematical and a
cogent-managerial interpretation of the beta
coefficient of each of the indicator variables.
5. Conduct an appropriate test to determine whether there is a
significant difference in the sales for territories in different
regions. Use α = 0.05. State the hypotheses, the test statistic,
the decision rule, your decision and conclusion.
6. Given an advertising expenditure = $50000 and the total bonus
paid in each territory = $25000, forecast the expected sales of a
territory (a) if it is in the South, (b) if it is the West and (c)
if it is in the Midwest.
4. For every additional amount spent on advertising in each territory, sales will increase by 1.5460.
For every additional amount of bonus paid in each territory, sales will increase by 1.1062.
For every geographic region in each territory, sales will increase by 118.8992.
5. The hypothesis being tested is:
H0: β3 = 0
H1: β3 ≠ 0
The test statistic is 4.145.
Decision rule: Reject Ho if p-value < 0.05.
The p-value is 0.0005.
Since the p-value (0.0005) is less than the significance level (0.05), we can reject the null hypothesis.
Therefore, we can conclude that there is a significant difference in the sales of territories in different regions.
6. (a) if it is in the South,
Sales = $1084.248 (in thousands of dollars)
(b) if it is the West and
Sales = $1203.147 (in thousands of dollars)
(c) if it is in the Midwest
Sales = $1322.047 (in thousands of dollars)
The output is:
R² | 0.920 | |||||
Adjusted R² | 0.909 | |||||
R | 0.959 | |||||
Std. Error | 68.888 | |||||
n | 25 | |||||
k | 3 | |||||
Dep. Var. | SALES | |||||
ANOVA table | ||||||
Source | SS | df | MS | F | p-value | |
Regression | 11,49,316.7391 | 3 | 3,83,105.5797 | 80.73 | 1.08E-11 | |
Residual | 99,657.0009 | 21 | 4,745.5715 | |||
Total | 12,48,973.7400 | 24 | ||||
Regression output | confidence interval | |||||
variables | coefficients | std. error | t (df=21) | p-value | 95% lower | 95% upper |
Intercept | -84.2192 | |||||
ADV | 1.5460 | 0.3061 | 5.050 | .0001 | 0.9094 | 2.1827 |
BONUS | 1.1062 | 0.5727 | 1.932 | .0670 | -0.0847 | 2.2971 |
REGION | 118.8992 | 28.6875 | 4.145 | .0005 | 59.2403 | 178.5581 |
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