The internet is fine for supplementary material for your paper like statistics and information on organizations, but not for the bulk of your research.
Think: Who would have the information you are looking for?
Ex: Statistics on Concussions: The Center for Disease Control and Prevention (CDC), part of the Dept. of Health and Human Services, compiles information on injuries and disease reported through hospitals and other healthcare sources. They would be the most reliable source for statistics on concussions.
If you are not familiar with the source, look for an 'About Us' page to find out if the person or organization presenting the information would be an expert in that area. If there is no information about who is responsible for the website, you don't know where the information came from.
Ask a librarian if you are not sure if your sources are the best ones for the information you are seeking.
When you use statistical information, it is not enough to simply say X% of people approve or disapprove of a certain issue. Opinions change over time and depend on the demographics of the group being polled. Note the following:
Who collected the data/took the poll?
When was this infomation collected?
What group was surveyed?
How big was the group?
What kind of information was being collected?
E.g. A 2015 Pew Research poll showed that although 63% of US adults surveyed said they get news through Twitter or Facebook, only 9% of Twitter users and 4% of Facebook users state that these services are the most important way they get their news (Barthel, Shearer, Gottfried, & Mitchell, 2015).
Be careful to note the language used in the data: e.g. 'most important' compared to 'important' or 'very important'.