# Statistics - Confidence Interval and Regression

12.48 In the following regression, X = weekly pay, Y = income tax withheld, and n = 35 McDonald's employees. (a) Write the regression equation. (b) Is the regression model significant? . (c) What is your conclusion about the slope? (d) In your own words, describe the fit of this regression. How well does the independent variable explain the dependent variable? Please see the attached file.

13.30 A researcher used stepwise regression to create regression models to predict BirthRate (births per 1,000) using five predictors: LifeExp (life expectancy in years), InfMort (infant mortality rate),

Density (population density per square kilometer), GDPCap (Gross Domestic Product per capita),

and Literate (literacy percent). Interpret these results. BirthRates2

14.16 (a) Plot the data on U.S. general aviation shipments. (b) Describe the pattern and discuss possible causes. (c) Would a fitted trend be helpful? Explain. (d) Make a similar graph for 1992-2003 only. Would a fitted trend be helpful in making a prediction for 2004? (e) Fit a trend model of your choice to the 1992-2003 data. (f) Make a forecast for 2004, using either the fitted trend model or a judgment forecast. Why is it best to ignore earlier years in this data set? Airplanes

[Please see the attached Question Fiel.]

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#### Solution Summary

Very neat - step-by-step solution with tend projects are provided.