Question 10.24

10.24 Income increases with age.

We see that older men do, on average, earn more than younger men, but the increase is not very rapid. (Note that the regression line describes many men of different ages—data on the same men over time might show a different pattern.)

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Figure 10.12: FIGURE 10.12 Excel output for the regression of income on age, Exercises 10.23–10.25.
  1. We know even without looking at the Excel output that there is highly significant evidence that the slope of the population regression line is greater than 0. Why do we know this?
  2. Excel gives a 95% confidence interval for the slope of the population regression line. What is this interval?
  3. Give a 99% confidence interval for the slope of the population regression line.

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