Problem 2.58 In the case (re: State vs. Pedro Soto et al.) the New Jersey Public Defender’s office moved to suppress evidence against 17 black defendants (principally on charges of transporting illegal drugs) on grounds of selective enforcement, i.e., that blacks were more likely to be stopped by the police than were others, on the southern portion of the New Jersey Turnpike. The following study was undertaken by the defense: For 30 days and for one hour each day, cars were observed traveling between Junctions 1 and 3 of the NJ Turnpike, and the number of speeding cars was recorded. An interesting feature of the data is that 98.1% of the cars observed were driving faster than the posted speed limit of 60 mph, consequently the state police could legally stop nearly anyone they chose. The driver’s racial identity (black or white) was recorded as well as the racial identities of the drivers who were stopped. The data collected are in the following table.

Driver Black White Total Stopped 127 148 275 Not Stopped 182 1605 1787 Total 309 1753 2062

(a) Compute the probability that a speeding driver is stopped.

(b) Suppose a speeding driver is stopped by the police; what is the probability that the driver is white?

(c) Suppose a speeding driver is white; what is the probability that the driver is stopped?

(d) Suppose a speeding driver is stopped by the police; what is the probability that the driver is black?

(e) Suppose a speeding driver is black; what is the probability that the driver is stopped? (f ) Do the data support, or refute, the defense claim of “racial profiling”? Justify your answer by referring to your answers to parts (a-e) above. Note: Justice Robert E. Francis of the Superior Court of New Jersey, in an unpublished opinion, found for the defense.