Apolling organization is checking its database to see if the data sources it used sampled the same zip codes. the variable datasource equals 1 if the data source is metromedia, 2 if the data source is dataqwest, and 3 if it's rolling poll. the organization finds that the correlation between five-digit zip code and datasource is minus0.0229. it concludes that the correlation is low enough to state that there is no dependency between zip code and source of data. comment.