Self-study
Dentist: Five recently conducted studies all show that Support the proportion of children with decayed, missing, or filled teeth is lower in Europe, where water is not fluoridated, than in the United States, where it is. ████ ██ ██████████ ████████ ████ ████████████ ██ █████ ████ ███ ████ █ ███████████ ████████ ██ ███████ █████ ██████
Summarize Argument: Phenomenon-Hypothesis
The dentist hypothesizes that fluoridated water doesn't significantly prevent tooth decay. She supports this by citing recent studies showing that in Europe, where water isn't fluoridated, the rate of tooth decay in children is lower than in the U.S., where water is fluoridated.
Notable Assumptions
The dentist overlooks other factors, like diet, oral hygiene, or healthcare access, that could affect tooth decay rates. She assumes water fluoridation doesn't prevent decay without considering that decay rates might be different to begin with.
10.
Which one of the following, ██ █████ █████ ████ ██████████ ███ █████████ █████████
a
Toothpaste containing fluoride ██ ██████ █████████ ██ ████ ███ ██████ ██████ ███ ███████
Just because fluoride toothpaste is widely available does not mean that children are using it. (A) doesn’t help to confirm the hypothesis that fluoridated water fails to prevent tooth decay.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
b
Nearly all dentists ██ ███ ██████ ██████ ███ ██████ ██████████ █████████ ███ ███████████ ██ ████████ ████████ ██ █████ █████████
Irrelevant— (B) does not imply that fluoride is therefore ineffective at preventing decay. We don’t know whether most children in the U.S. visit the dentist or whether all European dentists also apply fluoride to tooth surfaces.
c
Dental hygiene is █████████ ██████ ██ ██████████ ██████ ██ ████ ██████ ███ ███ ██████ ███████
Like (A), just because dental hygiene is taught in Europe and the U.S. doesn't mean that children then practice it. This doesn’t help to show that the fluoridation of water is the main difference in dental hygiene between American and European children.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
d
On average, children ██ ██████ ███████ ██████ ████████ ████ ██████████ ████ ████████ ██ ███ ██████ ███████
This weakens the argument by providing an alternative hypothesis to explain the differing rates of tooth decay. If European children receive more frequent dental care, it makes sense that they also have lower rates of tooth decay.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
e
The diets of ████████ ██ ███ ██████ ██████ ███ ███ █████████ █████ ███ █████ ████ █████ ██ ████████ ██ ███████
This strengthens the argument by eliminating an alternative hypothesis. If the diets of children in the United States are not worse for teeth, then diet is unlikely to be the cause of their tooth decay.
Alternate explanation
Alternate explanation
Weaken: Introduce or support an alternate explanation for a phenomenon.
Strengthen: Helps to eliminate an alternate explanation for a phenomenon.