SOLUTION FOR THIS PROBLEM

STAT 222 FALL 2017 HOMEWORK 3 – Due : 19 December 2017 Name, ID, & Signature ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ A statistics professor wanted to develop a model to predict how long individuals will live. After consulting a number of medical doctors, she collected the age at death (y), the average number of hours of exercise per week (x1), the cholesterol level (x2), and the number of points that the individual's blood pressure exceeded the recommended value (x3). A random sample of 40 individuals was selected. The computer output of the multiple regression model is shown below. THE REGRESSION EQUATION IS y = 55.8 + 1.79x1 ? 0.021x2 ? 0.061x3 Predictor Coef StDev T Constant 55.8 11.8 x1 1.79 0.011 x2 ?0.021 0.014 x3 ?0.016 0.44 ANALYSIS OF VARIANCE Source of Variation df SS MS F Regression * * * * Error * 3560 * Total 39 4166 a. Is there enough evidence at the 1% significance level to infer (or conclude) that the model is valid for predicting length of life? b. Calculate the coefficient of determination and interpret it. c. Is there enough evidence at the 10% significance level to infer (or conclude) that the average number of hours of exercise per week and the age at death are linearly related? d. Calculate the standard error of the estimate. What does this statistic tell you about the model?