Self-study
Medical researcher: At the Flegco Corporation, all employees whose work involves lifting heavy objects wear back belts to prevent back injuries. ████████ █ █████ █████ ████ ██████ █████████ ███ ████ ████ █████ ███ ████████ ████ ██████ ██ ██████ ████ ████████ ████ ███ █████████ ███ ██ ███ ████ ████ ██████ ████ ████████ ████ ████ █████ ██ ███ ████ ██ ███████ ████ █████████
Summarize Argument
The author concludes that back belts don’t help prevent back injuries. This is based on the fact that in a study of Flegco employees, those who wear back belts are more likely to suffer back injuries than employees who don’t wear back belts.
Identify and Describe Flaw
The author overlooks the possibility that the people who wear back belts at Flegco start off with a higher risk of back injuries than the people who don’t wear back belts. For example, maybe the people who wear back belts are involved in manual labor, whereas the people who don’t wear back belts are office workers who don’t lift anything heavy. If this is true, then we can’t conclude that back belts don’t reduce injuries simply because the people who wear back belts have more back injuries than the people who don’t wear the belts.
19.
The reasoning in the medical ████████████ ████████ ██ ████ ██████████ ██ █████████ ██ █████ ███ ██ ███ █████████ ████████
a
It compares the █████████ ██ ████ ██████ ███████ ███ ██████ ███ ████████ ██ ███ ████ ███ ████ ████ ███████ ███ ████ ███████
This points out that the people who wear back belts might be more at risk of back injury due to the nature of their job than are the people who don’t wear back belts. This is why the fact that the belt-wearers are more likely to get back injuries does not prove the belts don’t help reduce injuries.
b
It fails to ███████ ███ ███████████ ████ ██████ ███████████ █████████ ███ ████ ██████ ██ ████ ████ █████ ████ ███ █████████ ███ ███████ ███████ █████ ██ █████ █████████████
The argument concerns a comparison between Flegco employees. How Flegco employees compare to employees of other corporations is not relevant.
c
It takes for ███████ ████ ██ █ ██████ ██ ██████████ ████ ██ █████████ ██████████ ██ █ ███████ ███████ ████ ██████ ████ ████████ ██████████ ██ ████ ███████
The author does not assume that back belts causally contribute to back injuries. The conclusion is just that back belts do not help prevent back injuries. In other words, the author could believe back belts simply have no causal relationship to back injuries.
d
It confuses the █████ ████ █ ██████████ ████ ███ ████████ ██████████ ██ █ ███████ ██████ ████ ███ █████ ████ ████ ██████████ ████████ ███████████ ██ ██████████ ████ ███████
The author concludes that back belts do not help prevent back injuries. This claim is not confused for a claim that back belts do help prevent back injuries.
e
It fails to ███████ ███ ███████████ ████ ████ ██ █ ██████ ██ ██████████ ██ ███████ █ ███████ ███████ ███ ████████ ███ ███ ██ █████████ ██ █████ ███ ████ ██████ ██ ██ █████████
(E) describes a confusion of sufficient and necessary conditions. But there is no factor presented as sufficient to guarantee a certain effect. So there can’t be a confusion of sufficient and necessary conditions.