TABLE 14-11 A Weight-Loss Clinic Wants to Use Regression Analysis to Build

question 237

Multiple Choice

TABLE 14-11
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 + β₅X₁X₂ + ε
Partial output from Microsoft Excel follows:

-Referring to Table 14-11, 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 morning session.

• A) β₁ + β₄
• B) β₁ + β₅
• C) β₁
• D) β₄ + β₅

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Definitions:

Oxygenated Blood

Blood rich in oxygen, typically flowing from the lungs to the heart and then to the rest of the body.

Hepatic Portal Vein

A blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas, and spleen to the liver.

Superior Mesenteric Vein

A large vein that drains blood from the small intestine, ascending colon, and part of the large intestine into the portal vein.

Nutrient Blood

Blood enriched with nutrients absorbed from the digestive system, supplying essential nutrients to the body cells.