Which of the following is false regarding concrete strength tests?

A single strength test providing results that are more than 500 psi below the specified strength is indeed considered false because it violates standard acceptance criteria established for concrete. These criteria are in place to ensure that the structural integrity of concrete meets the design requirements; exceeding a deficiency of 500 psi indicates a significant shortfall in performance.

When evaluating concrete strength tests, it's important to remember that individual test results must adhere to minimum acceptable values. This includes not only the entirety of the testing framework but also the frequency of tests required to maintain compliance with the specified design strength. If multiple tests are conducted, no single test should fall below the acceptable limits, as this could potentially compromise the safety and durability of the structure.

The other statements are generally accurate interpretations of the guidelines governing concrete strength tests. The requirements help ensure that the concrete used in construction remains reliable and safe by adhering to predetermined strength standards.