Self-study
Scientists have long thought that omega-3 fatty acids in fish oil tend to lower blood cholesterol and strongly suspected that a diet that includes a modest amount of fish would provide substantial health benefits. ███ █████ █████ ████ ████████ ██████ ███████ ████ █ ██████ █████ ███████ ████ ███████████ ██████ ███ ███ ████ █████ █ ████ ███ ██████ ██ ███████ ████ ██████ ██ ███████ █████ ███████ ████ ███ █████ ███ ██ ███ ███ █████
Summary
A study found that middle-aged people who eat fish are less likely to develop heart disease than those who don’t. This supports the claims of some scientists, who suggest that fish oil lowers blood cholesterol and therefore eating fish is healthy.
Notable Assumptions
This argument conflates correlation with causation. It takes a study showing a correlation between eating fish and health, and suggests therefore that eating fish is good for health. There's an important assumption here, which could take multiple different forms, that the correlation can't be explained by some other reason besides eating fish reducing chances of heart disease. If the correlation between eating fish and lower heart disease risk wasn’t caused by eating fish but rather by some third thing, then the study doesn’t actually support the scientists’ view.
11.
Which one of the following ██ ██ ██████████ ████████ ██ ███ █████████
a
The test subjects ██ ███ ██████ █████ ███ ███ ███ ███ ████ ████ ███ ████████████
The fact that the non fish eaters were vegetarians isn’t necessary for the conclusion - if we negate this assumption, all it tells us is that fish eaters are healthier than vegetarians, which doesn’t change anything about the argument.
b
The test subjects ██ ███ ██████ █████ ███ ███ ████ █████ █ ████ ███ ███ ████ █ ████ ████ ███ █████████ █████████ ██ ███ ███████████ ██ █████ ████████
This answer goes the wrong way, which negating it demonstrates. If test subjects who ate fish had a diet that contributed to heart disease, the argument would be even stronger! The fish would look to be stopping the effects of the unhealthy diet.
c
The test subjects ██ ███ ██████ █████ ███ ███ ███ ███ ████ ████ █████████████ ████ ██████ ██ ███ ███ ████ ███████ █████ ███ ████ ████ ████ █████ ███ ███ ███ █████
If this were true, it would do more to hurt the argument than to support it. If the people who didn’t eat fish were eating red meat, then that might be another cause of the correlation that hurts the argument. The argument would have to assume the opposite of this.
d
The test subjects ██ ███ ██████ █████ ███ ███ ████ █████ █ ████ ████ ███ █████████████ ████ ██████ ████ █████ ███ ███ ███ ██ ██████ █████████ ██ ██████████ █████ ██ ███████ █████████████████ ███████
If this were not true - if the test subjects who ate fish were more likely to engage in other healthy activities, then that would be an alternate explanation of the correlation. The study’s findings would not be because eating fish is healthy, but instead because people who eat fish tend to be healthier in other ways.
e
The test subjects ██ ███ ██████ █████ ███ ███ ████ █████ █ ████ ████ ██ ████ ██████ ████ █████ ███ ███ ███ ██ ████ █████████ ████████████
This also goes the wrong direction, and negating it would actually help the argument, not undermine it. Negating (E) gives the claim that the fish eaters were more likely to be sedentary, which makes it look like the fish is doing even more to help counteract the effects of being sedentary.