Advanced Statistics Demystified
Offering exercises at the end of each chapter as well as two final exams, this self-teaching guide provides an effective, anxiety-soothing, and totally painless way to learn advanced statistics.
TABLE OF CONTENTS Advanced Statistics Demystified
Chapter 4: Multiple Regression
4-1 Multiple Regression Models
Rather than try to model a dependent variable by a single independent variable as is done in Chapter 3, sometimes we model the dependent variable by several independent variables. We may try to explain blood pressure not only by weight, but by age as well. We know that blood pressure tends to increase as weight increases but also increases as we age. To give another example, the price of a home may be modeled as a function of the number of baths, the number of bedrooms, the size of the lot, and the total square footage of a house.
In general, if y is the dependent variable and x 1, x 2, , x k are k independent variables, then the general multiple regression model has the general form
y = ? 0 + ? 1 x 1 + ? 2 x 2 + + ? kx k + ?
The part E( y) = ? 0 + ? 1 x 1 + ? 2 x 2 + + ? kx k is the deterministic portion of the model. The ? term is the random error term.
The assumptions of multiple regression are: (1) For any given set of values of the independent variables, the random error ? has a normal probability distribution with mean equal to 0 and...
Copyright The McGraw-Hill Companies, Inc. 2004 under license agreement with Books24x7
