Self-study
A person with a type B lipid profile is at much greater risk of heart disease than a person with a type A lipid profile. ██ ██ ███████████ ████ ████ █ ██████████ ███ ████ █ ██████████ ████ ███ ██ █ ███████ █████ ███ ███████████ ██████ ██ ███ ████ █ ██████████ ████ ███████ ██████████████ ████████ █████ █████ ████████ ████ ██████████ ███ ████ █ ███████████ ████████ ██████ ██ ███████ ████ ███ █████ ███ ██ ███████ ██ ████ ████████ ███████ ██ ████ █ █████████
Summary
People with type B lipid profiles experience much greater risk of heart disease than do people with type A lipid profiles.
An experiment was conducted in which type A and type B lipid profile volunteers were put on a low-fat diet. Their cholesterol levels and lipid profiles were monitored.
During the experiment, type B volunteers and type A volunteers showed very different results. Type B volunteers demonstrated lowered cholesterol levels but no change to their lipid profiles. Meanwhile, type A volunteers experienced no benefits and, in 40% of cases, actually shifted to type B lipid profiles.
Notable Valid Inferences
At the end of the experiment, 40% of type A volunteers were at greater risk of heart disease than they were at the beginning.
Changes in cholesterol levels do not necessarily correlate with changes in lipid profile types.
20.
If the information above is █████ █████ ███ ██ ███ █████████ ████ ████ ██ █████
a
In the experiment, ████ ██ ███ ██████████ ███ █████ ████ ██ █████ ███████ ███████ ██ █████ ██████████ ██ █ ██████ ██ ██████ ████ ███ ██ ███ █████
Could be false. Maybe there were 1,000 original type A volunteers and 10 type B! Also, we don’t know if the type B volunteers’ heart disease risk reduced. Maybe a factor other than cholesterol or lipid type changed during the experiment and counteracted the cholesterol changes.
b
People with type █ █████ ████████ ████ ██████ ███████████ ███████ ██ ████████ ████ ██ ██████ ████ ████ █ █████ █████████
Could be false. While we know that type B volunteers’ cholesterol dropped in the experiment, we don’t know how high their cholesterol actually was. Nor do we know anything about the type A lipid profile people’s cholesterol, other than that it did not change in the experiment.
c
Apart from adopting ███ ███████ █████ ████ ██ ███ ██████████ ███ ███ █████████████ ██████ ███ ██████ ██ █████ █████████ ████ █████ ████ ████████ █████ ███████████ ██████ ██ █████ █████████
Could be false. We have no idea what other behaviors volunteers engaged in during the experiment! That’s a reason why we can’t draw valid inferences about the actual impact of low-fat diets from the stimulus—we can only draw inferences about the results of this one experiment.
d
The reduction in ███████████ ██████ ██ ███ ██████████ ██ ██████ ███████████ ███ ███ ██████ ██ █████ █████ █████████
Must be false. The only volunteers who experienced a reduction in cholesterol levels (the original type B people) did not experience a change in their lipid profiles.
e
For at least ████ ██ ███ ██████████ ██ ███ ███████████ ███ ████ ██ █████ ███████ █████████ █████ ██████ ████ ███ ██ ███ ███████ █████
Must be true. People with a type B lipid profile are at greater risk of heart disease, so when 40% of the original type A volunteers experienced a shift to type B profiles and no benefits to counteract that change, they ended up at higher risk for heart disease.