1. STAT E100 Section Week 12- Regression

2. Course Review - Project due Dec 17 th, email your TA. - Exam 2 make-up is Dec 5 th, practice tests have been updated. - Email your TA to join the study group!

4. Concept Review

11. Sample Question #1 A survey was conducted in 4 sections of stat 104 trying to determine what factors lead to differences in resting heart rate. One variable that was of interest was amount exercise (in hours per week). Below are outputs from SPSS of the regression summary, scatterplot with fitted line, and the summary statistics for the exercise variable. The model used was: heartrate i = β 0 + β 1 * exercise i + ε i

12. Sample Question #1 A survey was conducted in 4 sections of stat 104 trying to determine what factors lead to differences in resting heart rate. One variable that was of interest was amount exercise (in hours per week). Below are outputs from SPSS of the regression summary, scatterplot with fitted line, and the summary statistics for the exercise variable. The model used was:

13. Sample Question #1 A survey was conducted in 4 sections of stat 104 trying to determine what factors lead to differences in resting heart rate. One variable that was of interest was amount exercise (in hours per week). Below are outputs from SPSS of the regression summary, scatterplot with fitted line, and the summary statistics for the exercise variable. The model used was:

14. . regress heartrate exercise Source | SS df MS Number of obs = 134 -------------+------------------------------ F( 1, 132) = 5.88 Model | 425.316813 1 425.316813 Prob > F = 0.0167 Residual | 9554.77274 132 72.384642 R-squared = 0.0426 -------------+------------------------------ Adj R-squared = 0.0354 Total | 9980.08955 133 75.0382673 Root MSE = 8.507 ----------------------------------------------------------------------------- heartrate| Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- exercise | -.3227266.1331379 -2.42 0.017 -.5860865 -.0593667 _cons | 67.71057.985429 68.71 0.000 65.76129 69.65984 ------------------------------------------------------------------------------ a) What is the correlation between exercise and heartrate? Is this correlation significant? Sample Question #1 (continued)

15. A survey was conducted in 4 sections of stat 104 trying to determine what factors lead to differences in resting heart rate. One variable that was of interest was amount exercise (in hours per week). Below are outputs from Stata of the regression summary, scatterplot with fitted line, and the summary statistics for the exercise variable. b) Calculate the 95% confidence interval for the true correlation between exercise and heartrate. c) What proportion of the total variability in heartrate does this model predict? d) What is the predicted heart rate for an individual who exercises 5 hours per week? Sample Question #1 (continued)