QMB 3200 Exam 3 Questions With Complete Solutions!

The variable selection procedure that identifies the best regression equation, given a specified number of independent variables, is: - ANSWERSbest-subsets regression. The mathematical equation that explains how the dependent variable y is related to several independent variables and has the form is called: - ANSWERSa multiple regression model. A regression model between sales ( in $1,000) and unit price (x1 in dollars) and television advertisement (x2 in dollars) resulted in the following function: . The coefficient of the unit price indicates that if the unit price is: - ANSWERSincreased by $1 (holding advertisement constant), the sales are expected to decrease by $3,000. If a categorical variable has k levels, then: - ANSWERSk - 1 dummy variables are needed. When constructing a confidence or a prediction interval to quantify the relationship between two quantitative variables, the appropriate degrees of freedom are: - ANSWERSn-2 Influential observations always: - ANSWERSNone of the above are correct. They can increase or decrease the value of the slope, correlation, and y-intercept depending on where they fall in relation to the rest of the points in the data set. The model developed from sample data that has the form is known as the: - ANSWERSestimated regression equation. When autocorrelation is present, which of the following assumptions is violated? - ANSWERSThe error terms are independent. - ANSWERShigh leverage points The mathematical equation relating the independent variable to the expected value of the dependent variable, , is known as the: - ANSWERS Dummy variables must always have: - ANSWERS When we conduct significance tests for a multiple regression relationship, the F test will be used as the test for: - ANSWERSoverall significance. When carrying out an F test to determine if the addition of extra predictor variables results in a significant reduction in the error sum of squares, what are the degrees of freedom of the numerator and denominator of the F statistic? - ANSWERSThe numerator degrees of freedom equals the number of predictors added to the model. The denominator degrees of freedom is n—p—1. How many independent variables does the forward selection process start with? - ANSWERSZero