It might be considered to be a biased test if how a person performs on the test is no indication of how they might perform on the job.
What is below, is from the following site:
Chesapeake Virginia To Pay Up Because Police Entrance Test Assumed Minorities Could Solve Simple Math Problems « Bad Cop News
"The lawsuit, filed last July in U.S. District Court, alleged that Chesapeake violated the Civil Rights Act of 1964 with its use of the math test as a screening device. The complaint argued that the pass/fail nature of the test did not predict future job performance yet resulted in a disproportionate impact on black and Hispanic applicants.
Between March 1, 2001, and Jan. 1, 2006, the city required applicants to score 70 percent or higher on the math portion of an entrance exam. A Justice Department review found just over 57 percent of black applicants and nearly 89 percent of white applicants passed.
“Any test used to select public safety officers must select the best and most qualified candidates without unfairly screening out qualified candidates,” said Wan J. Kim, an assistant attorney general for the Civil Rights Division.
The Justice Department concluded the discrimination was not intentional, Hallman said.
The Chesapeake Police have since changed their exam requirements to an average combined score of 66 percent on the math, reading comprehension and grammar tests, Hallman said. The Justice Department consented."