There is no such thing as a stupid question when one is seeking knowlege however the topic is more complex than a lot of people seem to realize.
The courts recognize that there is seldom "smoking gun evidence" of a person's intent to racially discriminate against another so they allow an inference to be made from the evidence. One of the questions that the EEOC asks and can be used to create a basis for an inference of racial discrimination is "How were you treated differently than others similarly situated as yourself?". This allows the complaintant/plaintiff to demonstrate how others with the same or similar circumstances, years of service, level of education, disciplinary history, etc. were treated more favorably, etc. than they were but there is more to it than just this.
The following case is the result of a investigation into religious and national origin discrimination but it contains information demonstrating how they conducted their investigation. Remember, it's not just racial discrimination that is unlawful. Discrimination due to your gender, any disabilities, sexual orientation, religion, national origin, etc.
Electroimpact to pay $485K over anti-Muslim harassment, retaliation claims | Washington State
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The complaint alleges that Zieve screened out applicants that affirmatively indicated that they were Muslim, or that Zieve perceived to be Muslim based on their name, photograph, national origin and/or application.
As a result, 94.5 percent of Electroimpact’s 474 engineers are white, according to a June 30, 2016 report to the U.S. Department of Labor. The complaint alleges that these practices make Electroimpact’s claim that it is an “equal opportunity employer” false advertising.
Electroimpact also maintained a listserv where employees discussed and shared “jokes.” Many emails and “jokes” posted to the listserv were demeaning to Muslims or those perceived to be Muslim.
For example, one employee emailed: “How do you save half the Muslims? Kill the other half.”
Zieve encouraged employees’ conduct on the listserv and often engaged in similar conduct."