Final answer:
A positive bias can enter into a radio report through bias by selection of sources, bias by spin, and framing.
Step-by-step explanation:
A positive bias can most likely enter into a radio report through several means. One way is through bias by selection of sources. This happens when a reporter only presents one side of the story or quotes experts who support a particular viewpoint. Another way is through bias by spin, where the reporter's subjective comments make one side's perspective look better than the other. Lastly, bias can also enter through framing, where the media packages and presents information in a way that encourages or discourages certain interpretations.