TABLE 17-6
A weight-loss clinic wants to use regression analysis to build a model for weight loss of a client (measured in pounds) .Two variables thought to affect weight loss are client's length of time on the weight-loss program and time of session.These variables are described below:
Y = Weight loss (in pounds)
X₁= Length of time in weight-loss program (in months)
X₂ = 1 if morning session,0 if not
X₃ = 1 if afternoon session,0 if not (Base level = evening session)
Data for 12 clients on a weight-loss program at the clinic were collected and used to fit the interaction model:
Y = β₀ + β₁X₁ + β₂X₂ + β₃X₃ + β₄X₁X₂ + β₅X₁X₃ + ε
Partial output from Microsoft Excel follows:
Regression Statistics ANOVA
F = 5.41118 Significance F = 0.040201
-Referring to Table 17-6,in terms of the βs in the model,give the mean change in weight loss (Y) for every 1-month increase in time in the program (X₁) when attending the evening session.

Question

TABLE 17-6
A weight-loss clinic wants to use regression analysis to build a model for weight loss of a client (measured in pounds) .Two variables thought to affect weight loss are client's length of time on the weight-loss program and time of session.These variables are described below:
Y = Weight loss (in pounds)
X₁= Length of time in weight-loss program (in months)
X₂ = 1 if morning session,0 if not
X₃ = 1 if afternoon session,0 if not (Base level = evening session)
Data for 12 clients on a weight-loss program at the clinic were collected and used to fit the interaction model:
Y = β₀ + β₁X₁ + β₂X₂ + β₃X₃ + β₄X₁X₂ + β₅X₁X₃ + ε
Partial output from Microsoft Excel follows:
Regression Statistics

ANOVA
F = 5.41118 Significance F = 0.040201

-Referring to Table 17-6,in terms of the βs in the model,give the mean change in weight loss (Y) for every 1-month increase in time in the program (X₁) when attending the evening session.

Quizplus · Accepted Answer

The coefficient of X₁ (length of time in the program) is β₁, which represents the mean change in weight loss for every 1-month increase in time in the program, holding the session time constant at the base level (evening session). The coefficients for X₂, X₃, X₄, and X₅ represent the differences in weight loss associated with attending morning or afternoon sessions and the interaction effects between session time and length of time in the program. But the question specifically asks for the mean change in weight loss for a 1-month increase in time in the program when attending the evening session.

TABLE 17-6 A Weight-Loss Clinic Wants to Use Regression Analysis to Build