Final answer:
A negative test result means that the substance is not detected, which may be due to low levels or testing errors. The alpha level in testing indicates the probability of a false positive, and specificity refers to correctly identifying non-diseased individuals.
Step-by-step explanation:
A negative test result generally indicates that the agent or substance being tested for is not detected in the sample. It doesn't necessarily mean that the agent is not active, present, nor that it cannot be tested for—it may be that the agent is present but the level is below the detection limit of the test, or there may have been an error in the test procedure leading to a false negative. In diagnostic testing, there are parameters such as the test sensitivity and specificity that affect the accuracy of the results.
A test's specificity is its ability to correctly identify those without the disease; a high specificity means that fewer non-diseased individuals are incorrectly labeled as having the disease. Conversely, test sensitivity is the ability to correctly identify those with the disease. Therefore, when a screening test for tuberculosis (TB) has an alpha level of 0.10, it means that there is a 10% chance of incorrectly rejecting the null hypothesis (which states the patient does not have TB) when it is, in fact, true.