What Affects Flat Panel LCD TV Sales? Flat Panel LCD $\text {Dependent Variable is Sales}$

question 15

Essay

What affects flat panel LCD TV sales? Flat panel LCD TV's are sold through a
variety of outlets such as large and small electronics stores, department stores, large
discount chains and online. Sales figures (number of units) for the popular Sony Bravia
were obtained for last quarter from a sample of 30 different stores. Also collected were
data on the selling price and amount spent on advertising the Sony Bravia (as a
percentage of total advertising expenditure in the previous quarter) at each store. Below
are the multiple regression results. $\text {Dependent Variable is Sales}$

$\begin{array} { l r r r r } \text { Predictor } & \text { Coef } & \text { SE Coef } & \text { T } & \text { P } \\ \text { Constant } & 90.19 & 25.08 & 3.60 & 0.001 \\ \text { Price } & - 0.03055 & 0.01005 & - 3.04 & 0.005 \\ \text { Advertising } & 3.0926 & 0.3680 & 8.40 & 0.000 \end{array}$

$$S = 10.6075 \quad \mathrm { R } - S q = 84.48 \quad \mathrm { R } - S q ( a d j ) = 83.3\%$$
$\text {Analysis of Variance}$

$\begin{array} { l r r r } \text { Source } & \text { DF } & \text { SS } & \text { MS } \\ \text { Regression } & 2 & 16477.3 & 8238.7 \\ \text { Residual Error } & 27 & 3038.0 & 112.5 \\ \text { Total } & 29 & 19515.4 & \end{array}$
a. Write out the estimated regression equation.
b. Is the regression equation significant overall? Explain.
c. How much of the variability in Sales is explained by the regression equation?
d. State the hypotheses for testing the regression coefficient of Price. Based on the
results, what do you conclude?
e. State the hypotheses for testing the regression coefficient of Advertising Expenditure.
Based on the results, what do you conclude?
f. Predict the sales for a store that sells the Sony Bravia for $2199 and spends 10% of its
advertising budget on the product.
g. Comment on whether the conditions for multiple regression are satisfied based on the
plots shown below.