Recently, the annual number of driver deaths per 100,000 for the selected age groups was as follows:
| Age | Number of Driver Deaths per 100,000 |
| 16–19 | 38 |
| 20–24 | 36 |
| 25–34 | 24 |
| 35–54 | 20 |
| 55–74 | 18 |
| 75+ | 28 |
- For each age group, pick the midpoint of the interval for the x value. (For the 75+ group, use 80.)
- Using “ages” as the independent variable and “Number of driver deaths per 100,000” as the dependent variable, make a scatter plot of the data.
- Calculate the least squares (best–fit) line. Put the equation in the form of: ŷ = a + bx
- Find the correlation coefficient. Is it significant?
- Predict the number of deaths for ages 40 and 60.
- Based on the given data, is there a linear relationship between age of a driver and driver fatality rate?
- What is the slope of the least squares (best-fit) line? Interpret the slope.
OpenStax Introductory Statistics 2e, 12.5 Prediction, exercise 23