https://www.nytimes.com/interactive/2020/11/03/us/elections/exit-polls-president.html
Before you go laughing at NYT, read rhetoric disclaimer and research what is required for a case study.
"The numbers on this page are estimates from exit polls conducted by Edison Research for the National Election Pool. These surveys interviewed voters outside of polling places or early voting sites, or by phone (to account for mail-in voters).
Results from interviews with 15,590 voters are shown below. These numbers have been adjusted to match the actual vote count.
While exit polls offer an initial indication of how groups voted on election night, they are not perfect. The polls are not precise enough to distinguish between, say, 53 percent support or 50 percent support from a certain group. Like any survey, they are subject to sampling error, and they rely on estimates of how many people voted in each group"