Question 17·Medium·Inferences
To curb hospital-acquired infections, a clinic replaced standard plastic bed rails with copper alloy rails, which laboratory studies suggest kill many bacteria on contact. Over six months, patient infection rates in rooms with copper rails were 35% lower than rates in otherwise identical rooms with standard rails. The clinic maintained the same cleaning protocols in all rooms throughout the study. Consequently, the copper rails most likely ______
Which choice most logically completes the text?
For questions asking what “most logically completes” a text about a study or experiment, first identify the variables: what changed (the treatment) and what stayed the same (controls). Then focus on the stated result (here, a 35% reduction) and choose the option that links the change to that result without adding new causes or contradicting details. Quickly eliminate answers that introduce behaviors or conditions not mentioned (like new cleaning routines or habits) or that deny the clear effect described in the passage.
Hints
Locate the key comparison
Underline the parts that compare the rooms with copper rails to the rooms with standard rails. What is the one main difference between the two kinds of rooms?
Use the detail about cleaning protocols
The passage says the clinic "maintained the same cleaning protocols in all rooms." How does this affect what we can say about the role of cleaning versus the role of the rails?
Watch out for new, unstated causes
Look for answer choices that introduce new ideas, such as changes in how often people washed their hands or how often the rooms were cleaned. Are those mentioned anywhere in the passage?
Match the conclusion to the 35% figure
The passage gives a specific result: infection rates were 35% lower in one group of rooms. Which choice describes a conclusion that fits that result without exaggerating or contradicting it?
Step-by-step Explanation
Understand the setup of the study
The passage describes a comparison between two types of hospital rooms:
- One group has standard plastic bed rails.
- The other group has copper alloy rails, which lab studies suggest can kill bacteria.
The clinic kept everything else the same, especially the cleaning protocols, in all rooms.
Focus on the result and what changed
The result given is: over six months, infection rates in rooms with copper rails were 35% lower than infection rates in otherwise identical rooms with standard rails.
The key logical idea:
- If only the rails are different between the two groups of rooms,
- and the rooms with copper rails have lower infection rates,
- then the difference in infection rates is most likely due to the copper rails.
Eliminate choices that contradict or add new, unsupported ideas
Check each type of wrong answer:
- Any choice that says there was no impact cannot be right, because a 35% reduction is clearly an impact.
- Any choice that claims a change in cleaning routines is unsupported, because the passage explicitly says cleaning stayed the same.
- Any choice that claims a change in people’s behavior (like more handwashing) is also unsupported, because the passage never mentions such a change.
So we want the option that simply and logically connects copper rails to the reduced infections, without inventing extra details.
Choose the conclusion that follows from the evidence
Because cleaning was identical in all rooms, but infection rates were 35% lower in rooms with copper rails, the best conclusion is that the copper rails lowered infection rates in addition to what the same cleaning protocols would have done on their own.
Therefore, the correct answer is:
A) reduced infections beyond what identical cleaning alone would have achieved.