Reading a Machine Log: Two Words in Context
A shift supervisor at a packing plant is writing up a sealing unit for the maintenance log. Over three weeks the unit jammed 0, 4, 0, 0, 3, 0, 5, 0, 0, 0, 2, 0, 0, 4, and 0 times on successive shifts. There is no pattern in when it fails, and no adjustment has changed the rate. She writes: "Jams on the sealing unit have been sporadic, and no single cause has been identified." Her manager, reading quickly, asks whether she means the jams are getting worse. A second line in her draft reads: "The vendor's provisional fix - retightening the guide rail - held for one shift only."
1. In the sentence she wrote, what does "sporadic" most nearly mean? Support your answer with the numbers in the log, and explain why "constant" and "increasing" would both be wrong.
Read the worked answer
Meaning: occurring at irregular intervals - happening now and then, with no predictable schedule.
Evidence from the log
- Ten of the fifteen shifts show zero jams.
- The non-zero shifts are 4, 3, 5, 2, and 4 - scattered, not on consecutive shifts.
- The supervisor states outright that there is no pattern and that no adjustment has changed the rate.
Why "constant" fails: a constant problem would jam on most or all shifts. Ten clean shifts contradict that.
Why "increasing" fails: the counts 4, 3, 5, 2, 4 rise and fall with no upward trend, and the passage says the rate has not changed. The manager's question rests on a misreading.
So the word signals intermittent and unpredictable, which is exactly what the numbers show.
2. Which rewrite preserves the supervisor's meaning - "The jams occur at irregular intervals" or "The jams occur at regular intervals"? Explain how the rest of the passage settles it.
Read the worked answer
Correct rewrite: "The jams occur at irregular intervals."
Why: The log shows failures mixed unpredictably with clean shifts, and the supervisor explicitly says there is no pattern. "Irregular" matches that evidence; "regular" would claim a repeating schedule the log does not show.
The trap: "regular" and "irregular" look like near-twin words, so a rushed reader may treat them as interchangeable. They are opposites on the one feature that matters here - predictability.
Test: If the jams were regular, the supervisor could forecast the next one and would not be writing "no single cause has been identified" as an open problem. Her whole purpose in the line is to say the failures cannot be scheduled or anticipated.
3. What does "provisional" mean as it is used in the second line, and which detail in the passage establishes that meaning?
Read the worked answer
Meaning: temporary or tentative - put in place to serve for now, subject to being replaced.
Establishing detail: the fix "held for one shift only." A repair that lasts a single shift cannot be a permanent solution, so the word must be marking it as a stopgap.
How the context does the work: "provisional" sits directly beside the action (retightening a guide rail) and its outcome (one shift of relief). A reader who has never seen the word can still infer "not final" from that pairing.
What it does not mean: it says nothing about whether the fix was cheap, approved, or skilled. Those are tempting guesses, but the sentence gives no evidence for any of them - only that the repair was short-lived and therefore not the real answer.