Final answer:
The least likely first step in diagnosing a problem, like a car not starting, is to start with the most difficult test. It's more efficient to gather information, perform simple initial tests, eliminate the customer's complaint, and then progress to more complex tests if necessary.
Step-by-step explanation:
The least likely first step in a diagnosis would be to start with the most difficult test. When diagnosing an issue, such as a car not starting, following a systematic approach is crucial for an efficient diagnosis. Typically, this involves asking questions to the customer to acquire more information, performing initial simple tests based on a hypothesis, and ensuring that the initial customer complaint is addressed before escalating to more complex diagnostic procedures.
For instance, if a car won't start, a reasonable first test would inspect the oil level under the hood before moving on to more elaborate tests. Road tests are often employed, but these are usually not the very first step unless they serve a clear purpose in confirming the initial hypothesis. Therefore, conducting the most difficult test first goes against the logical flow of troubleshooting and is not advised.