Goal congruence in top management teams. Do chief executive officers (CEOs) and their top managers always agree on the goals of the company? Goal importance congruence between CEOs and vice presidents (VPs) was studied in the Academy of Management Journal (Feb. 2008). The researchers used regression to model a VP’s attitude toward the goal of improving efficiency (y) as a function of the two quantitative independent variables level of CEO (x1)leadership and level of congruence between the CEO and the VP (x2). A complete second-order model in x1and x2was fit to data collected for n = 517 top management team members at U.S. credit unions.

a. Write the complete second-order model for E(y).

b. The coefficient of determination for the model, part a, was reported asR2=0.14. Interpret this value.

c. The estimate of theβ-value for the(x2)2term in the model was found to be negative. Interpret this result, practically.

d. A t-test on theβ-value for the interaction term in the model,x1x2, resulted in a p-value of 0.02. Practically interpret this result, usingα=0.05.

Short Answer

Expert verified

a. The complete second-order model equation for x1and x2is.E(y)=β0+β1x1+β2x2+β3x1x2+β4x12+β5x22

b. 14% is a very low value for R2and thus the model is not an ideal fit for the data.

c. The value of β5indicates the curvature of the parabola due to the changes in the value of x2. Here a negative value means that the parabola will be a downward shaping curve.

d. At 95% confidence interval, β30.

Step by step solution

01

Second-order equation

The complete second-order model equation for x1and x2isE(y)=β0+β1x1+β2x2+β3x1x2+β4x12+β5x22

02

Interpretation of R2

The value of R2is said to be 0.14 which indicates that almost 14% of the variation in the variables is explained by the model. A higher value denotes that the model is a good fit for the data while a lower value denotes that the model is not an ideal fit for the data. 14% is a very low value for R2and thus the model is not an ideal fit for the data.

03

Analysis of β5

The value of β5indicates the curvature of the parabola due to the changes in the value of x2. Here a negative value means that the parabola will be a downward shaping curve.

04

Simplification of β3

H0:β3=0whileHa:β30

The p-value of β3is 0.02 while α=0.05.

H0is rejected ifp-value < α. For α=0.05, since0.02<0.05

Sufficient evidence to rejectH0at 95% confidence interval.

Therefore,β30.

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Most popular questions from this chapter

Question: The complete modelE(y)=β0+β1x1+β2x2+β3x3+β4x4+εwas fit to n = 20 data points, with SSE = 152.66. The reduced model,E(y)=β0+β1x1+β2x2+ε, was also fit, with

SSE = 160.44.

a. How many β parameters are in the complete model? The reduced model?

b. Specify the null and alternative hypotheses you would use to investigate whether the complete model contributes more information for the prediction of y than the reduced model.

c. Conduct the hypothesis test of part b. Use α = .05.

Question: Personality traits and job performance. Refer to the Journal of Applied Psychology (Jan. 2011) study of the relationship between task performance and conscientiousness, Exercise 12.54 (p. 747). Recall that the researchers used a quadratic model to relate y = task performance score (measured on a 30-point scale) to x1 = conscientiousness score (measured on a scale of -3 to +3). In addition, the researchers included job complexity in the model, where x2 = {1 if highly complex job, 0 if not}. The complete model took the form

E(y)=β0+β1x1+β2x12+β3x2+β4x1x2+β5x12x2herex2=1E(y)=β0+β1x1+β2x12+β3(1)+β4x1(1)+β5(1)2(1)E(y)=(β0+β3)+(β1+β4)x1+(β2+β5)(x1)2

a. For jobs that are not highly complex, write the equation of the model for E1y2 as a function of x1. (Substitute x2 = 0 into the equation.)

b. Refer to part a. What do each of the b’s represent in the model?

c. For highly complex jobs, write the equation of the model for E(y) as a function of x1. (Substitute x2 = 1 into the equation.)

d. Refer to part c. What do each of the b’s represent in the model?

e. Does the model support the researchers’ theory that the curvilinear relationship between task performance score (y) and conscientiousness score (x1) depends on job complexity (x2)? Explain.

Question: After-death album sales. When a popular music artist dies, sales of the artist’s albums often increase dramatically. A study of the effect of after-death publicity on album sales was published in Marketing Letters (March 2016). The following data were collected weekly for each of 446 albums of artists who died a natural death: album publicity (measured as the total number of printed articles in which the album was mentioned at least once during the week), artist death status (before or after death), and album sales (dollars). Suppose you want to use the data to model weekly album sales (y) as a function of album publicity and artist death status. Do you recommend using stepwise regression to find the “best” model for predicting y? Explain. If not, outline a strategy for finding the best model.

Question: Bordeaux wine sold at auction. The uncertainty of the weather during the growing season, the phenomenon that wine tastes better with age, and the fact that some vineyards produce better wines than others encourage speculation concerning the value of a case of wine produced by a certain vineyard during a certain year (or vintage). The publishers of a newsletter titled Liquid Assets: The International Guide to Fine Wine discussed a multiple regression approach to predicting the London auction price of red Bordeaux wine. The natural logarithm of the price y (in dollars) of a case containing a dozen bottles of red wine was modelled as a function of weather during growing season and age of vintage. Consider the multiple regression results for hypothetical data collected for 30 vintages (years) shown below.

  1. Conduct a t-test (atα=0.05 ) for each of the βparameters in the model. Interpret the results.
  2. When the natural log of y is used as a dependent variable, the antilogarithm of a b coefficient minus 1—that is ebi - 1—represents the percentage change in y for every 1-unit increase in the associated x-value. Use this information to interpret each of the b estimates.
  3. Interpret the values of R2and s. Do you recommend using the model for predicting Bordeaux wine prices? Explain

Question: Tipping behaviour in restaurants. Can food servers increase their tips by complimenting the customers they are waiting on? To answer this question, researchers collected data on the customer tipping behaviour for a sample of 348 dining parties and reported their findings in the Journal of Applied Social Psychology (Vol. 40, 2010). Tip size (y, measured as a percentage of the total food bill) was modelled as a function of size of the dining party(x1)and whether or not the server complimented the customers’ choice of menu items (x2). One theory states that the effect of the size of the dining party on tip size is independent of whether or not the server compliments the customers’ menu choices. A second theory hypothesizes that the effect of size of the dining party on tip size is greater when the server compliments the customers’ menu choices as opposed to when the server refrains from complimenting menu choices.

a. Write a model for E(y) as a function of x1 and x2 that corresponds to Theory 1.

b. Write a model for E(y) as a function of x1and x2that corresponds to Theory 2.

c. The researchers summarized the results of their analysis with the following graph. Based on the graph, which of the two models would you expect to fit the data better? Explain.

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