 mask, and 0 if they are not. Suppose that if the driver wears a mask (mask = 1), they are not arrested (outcome = 0), but if they do not wear a mask (mask = 0), they are arrested (outcome = 1). The causal effect of wearing a mask for this driver is the difference in outcomes: 
0−1=−1, meaning that wearing a mask reduced the chance of arrest for this individual. </td>
  </tr>
  <tr>
   <td style="text-align:left;"> introduction-12 </td>
   <td style="text-align:left;"> question </td>
   <td style=