It is important to determine how credible a given source of information is before you quote it or use it as a basis for decision making. If you find an article using a library resource, the name of the author and publication will always be included; if you are searching on Google, be sure you can identify an author, date, and publication.
If you are looking for statistics on Google, only use ones that are clearly attributed to a source of information. Any .gov site will cite where the statistics are coming from - these tend to be good sources of information.
When in doubt, ask me or your instructor for help in determining the quality of a source.