7. A non-transitory computer readable medium encoded with a computer program that includes instructions to cause a processor to: receive a first set of scan data that includes information regarding wireless access points available to each device of the first group; compute a set of statistics for each of multiple subsets of devices of the first group based on the first set of scan data; classify each of the subsets of devices in one of multiple proximity classes; train a model to classify the subsets of devices in the respective proximity classes based on the respective sets of statistics; receive a second set of scan data that includes information regarding wireless access points available to each device of a second group; compute the set of statistics for the second group of devices based on the second set of scan data; and classify the second group of devices in one of the proximity classes based on the set of statistics of the second group and the model.
7. A non-transitory computer readable medium encoded with a computer program that includes instructions to cause a processor to: receive a first set of scan data that includes information regarding wireless access points available to each device of the first group; compute a set of statistics for each of multiple subsets of devices of the first group based on the first set of scan data; classify each of the subsets of devices in one of multiple proximity classes; train a model to classify the subsets of devices in the respective proximity classes based on the respective sets of statistics; receive a second set of scan data that includes information regarding wireless access points available to each device of a second group; compute the set of statistics for the second group of devices based on the second set of scan data; and classify the second group of devices in one of the proximity classes based on the set of statistics of the second group and the model. 10. The non-transitory computer readable medium of claim 7 , further including instructions to cause the processor to: compute the set of statistics for pairs of devices of the first group.