The document provides information on key media planning concepts such as base, audience number, circulation, coverage, reach, frequency, gross rating points (GRPs), and gross impressions. It explains that a base is a demographic group, audience number depends on how exposure is measured, and circulation does not provide demographic data. Coverage measures the percentage of a target market exposed to a media vehicle. GRPs represent the sum of ratings for a media plan disregarding audience duplication, while gross impressions represent the sum of individual audience sizes.