In a simulation of 30 mobile computer networks, the

Chapter 8, Problem 5SE

(choose chapter or problem)

In a simulation of 30 mobile computer networks, the average speed, pause time, and number of neighbors were measured. A “neighbor” is a computer within the transmission range of another. The data are presented in the following table.

a. Fit the model with Neighbors as the dependent variable, and independent variables Speed, Pause, \(\mathrm {Speed \cdot Pause}\), \(\mathrm {Speed}^2\), and \(\mathrm {Pause}^2\).

b. Construct a reduced model by dropping any variables whose P-values are large, and test the plausibility of the model with an F test.

c. Plot the residuals versus the fitted values for the reduced model. Are there any indications that the model is inappropriate? If so, what are they?

d. Someone suggests that a model containing Pause and \(\mathrm {Pause}^2\) as the only dependent variables is adequate. Do you agree? Why or why not?

e. Using a best subsets software package, find the two models with the highest \(R^2\) value for each model size from one to five variables. Compute \(C_p\) and adjusted \(R^2\) for each model.

f. Which model is selected by minimum \(C_p\)? By adjusted \(R^2\)? Are they the same?

Equation Transcription:

Text Transcription:

Speed{cdot}Pause

Speed^2

Pause^2

Pause^2

R^2

C_p

R^2

C_p

R^2