# 1)The director of marketing at Vanguard Corporation believes the sales of the company’s Bright Side Laundry detergent (S) are related to Vanguard’s own advertising expenditure (A), as well as the combined advertising expenditures of its three biggest riva

1)The director of marketing at
Vanguard Corporation believes the
sales of the company’s Bright Side
Laundry detergent (S) are related to
expenditure (A), as well as the
of its three biggest rival
detergents R). The marketing
director collects 36 weekly
observations on S, A, and R to
estimate the following multiple
regression equation:

S = a + bA + cR

Where S, A, R are measured in
dollars per week. Vanguard’s
marketing director is comfortable
using parameter estimates that are
statistically significant at the
10 percent level or better.

a) What sign does the marketing
director expect a, b, and c to have?
b) Interpret the coefficients a, b,
and c?

The regression output from the
computer is as follows:

Dependant Variable: S
Observations: 36
R-Square: 0.2247 F-Ratio: 4.781
P-value on F: 0.0150
Variable: Intercept
Parameter Est: 175086.0
Standard Error: 63821.0
T-Ratio: 2.74
P-Value: 0.0098
Variable: A
Paramter estimate: 0.8550
Standard Error: 0.3250
T-Ratio: 2.63
P-Value: 0.0128
Variable: R
Parameter Est: – 0.284
Standard Err: 0.164
T-ratio: – 1.73
P-Value: 0.0927

expenditure have a statistical
significant effect on the sales of
Bright Side detergent? Explain,
using appropriate p-value……
d) Does the advertising by its three
largest rivals affect sales of
Bright Side detergent in a
statistical significant way?
Explain using the appropriate
p-value…….
e) What fraction of the total
variation in sales of Bright Side
remains unexplained?
What can the marketing director do
to increase the explanatory power
of the sales equation?
What other explanatory variables
might be added to this equation?
f) What is the expected level of sales
each week when Vanguard spends
\$40,000 per week and the combined