> > U n a n s W e r e d O u e s 1 I o n s IUO Also of interest is whether there are any differences in the waiting time distributions by self reported race of the survey participants. Participants classified themselves into 1 of 3 racial categories: while, black, other (did not identify as either black or white). Following are the results from a simple regression performed to relate waiting time to race: 9 :515 +19.3X1+ 2.6x; where X1:1 if the respondent identifies as black (and 0 if not), and x221 if the participant identifies as other (0 if not). The standard error of the slope for x1 is 1.2, and for X2 is 2.5. The R2 is 0.01. -Based on these regression results, what is the estimated mean difference in waiting times (and 95% CI) for Blacks compared to Whites? I: a. 51.5 minutes; (50.0, 53.0) minutes I: b. 19.3 minutes; (16.9, 21.7) minutes I: c. 2.6 minutes ; (2.4, 7.6) minutes I V'\""\