A sample IELTS question in the reading section concerns a passage about how dentistry has improved over the last few centuries. The passage includes:
Modern dentistry was in its infancy for most of the 18th and the beginning of the 19th century and for the average person, the only solution to tooth decay would be extraction. ...
In addition, the practice of selling one's teeth to wealthy people in exchange for a meager amount of money wasn't uncommon in the Victorian era either. Human teeth were the preferred choice for the production of dentures...
Though the thought of having healthy teeth removed with pliers and with no anaesthetic... may seem ... unwise to modern readers, for many desperately poor Victorian people, including children, this was often one of the few ways to provide for themselves or their families.
The question asks:
Does the following statement reflect the claims of the writer? Answer
YES if the statement reflects the claims of the writer
NO if the statement contradicts the claims of the writer
NOT GIVEN if it is impossible to say what the writer thinks about this.
The statement is:
Healthy individuals in the Victorian Era didn't generally have their decayed teeth extracted.
The official correct answer is NOT GIVEN. The explanation cites a subset of the quoted text above:
"for the average person, the only solution to tooth decay would be extraction."
I would have thought the answer would be NO because of the cited text and the fact that healthy individuals had even healthy teeth extracted, so having decayed teeth extracted would seem implied as a relatively common practice. This answer does require some assumed correlation between "average" and "healthy" people, but the test applies the adjective "healthy" to people with decayed teeth and the passage makes no explicit difference between these sets (nor does the passage suggest that the average person was unhealthy beyond tooth decay).
Is there really no correlation that can be assumed between those groups? Or is there an extra negative or other factor I'm overlooking here?