1. In the coal mining example, a regression of the fatality rate on the regulation dummy variable gives the results in Figure 21.11.5, whereas a regression of the
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![1270_mining.png](https://secure.tutorsglobe.com/CMSImages/1270_mining.png)
Figure 21.11.5. Coal mining regression results.
![123_mining2.png](https://secure.tutorsglobe.com/CMSImages/123_mining2.png)
Figure 21.11.6. Coal mining regression results with a trend term.
fatality rate on the regulation dummy variable and a trend term gives the results in Figure 21.11.6. Explain why the coefficient estimate for R changes. Be sure to discuss the relationship between R and Trend in your answer.