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

question 32

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
Data for 25 clients on a weight-loss program at the clinic were collected and used to fit the interaction model:
Y = β₀ + β₁X₁ + β₂X₂ + β₃X₁X₂ + ε
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 on the program (X₁) when not attending the morning session.

• A)β₁
• B)β₁ + β₂
• C)β₁ + β₃
• D)β₂ + β₃

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Definitions:

Dependent Variable

A variable in an experiment or model that is expected to change in response to changes in independent variables.

Perfect Correlation

Perfect correlation occurs when two variables move in unison, either directly (perfect positive correlation) or inversely (perfect negative correlation), with a correlation coefficient of +1 or -1, respectively.

Perfect Prediction

A situation where a model or analysis predicts the outcome with 100% accuracy, with no errors.

Regression Equation

An equation that describes the line of best fit through a dataset, used to predict the outcome variable.