Instruction 13.21 A Weight-Loss Clinic Wants to Use Regression Analysis to Build

Multiple Choice

Instruction 13.21
A weight-loss clinic wants to use regression analysis to build a model for weight-loss of a client (measured in kilograms) . Two variables thought to effect 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 kilograms)
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:

-In a multiple regression model,the adjusted r²

A) can sometimes be negative.
B) can sometimes be greater than +1.
C) cannot be negative.
D) has to fall between 0 and +1.