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Regression Analysis - Independent and Dependent Variables

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1. Conduct a regression analysis to determine if age (independent variable) has any effect on the number of vitamins/supplements people take. State what you are testing and what the x (independent) and y (dependent) variables are. Test for correlation and explain the regression results, if necessary.

2. Conduct a regression analysis to determine if age (independent variable) has any effect on the number of alcoholic beverages someone consumes in one month. State what you are testing and what the x (independent) and y (dependent) variables are. Test for correlation and explain the regression results, if necessary.

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Solution Summary

This solution contains two similar problems on how to perform a correlation and a regression analysis. The first solution explains how to determine whether age affects on the intake of vitamin supplements on a given data, based on a correlation and a regression analysis. The second solution analyzes whether age affects on the consumption of alcoholic beverages, also based on a given data.

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Statistics Problems - Regression Analysis, Autocorrelation, Multicollinearity

1. Suppose an appliance manufacturer is doing a regression analysis, using quarterly time-series data, of the factors affecting its sales of appliances. A regression equation was estimated between appliance sales (in dollars) as the dependent variable and disposable personal income and new housing starts as the independent variables. The statistical tests of the model showed large t-values for both independent variables, along with a high r2 value. However, analysis of the residuals indicated that substantial autocorrelation was present.

a. What are some of the possible causes of this autocorrelation?

b. How does this autocorrelation affect the conclusions concerning the significance of the individual explanatory variables and the overall explanatory power of the regression model?

c. Given that a person uses the model for forecasting future appliance sales, how does this autocorrelation affect the accuracy of these forecasts?

d. What techniques might be used to remove this autocorrelation from the model?

2. Suppose the appliance manufacturer discussed in Exercise 1 also developed another model, again using time-series data, where appliance sales was the dependent variable and disposable personal income and retail sales of durable goods were the independent variables. Although the r2 statistic is high, the manufacturer also suspects that serious multicollinearity exists between the two independent variables.

a. In what ways does the presence of this multicollinearity affect the results of the regression analysis?

b. Under what conditions might the presence of multicollinearity cause problems in the use of this regression equation in designing a marketing plan for appliance sales?

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