Self-study
Several people came down with an illness caused by a type of bacteria in seafood. ██████ █████████ ██████ ███ ███████ ██ ████ ██████ ███ ██████ ███ ██ ███ ████ ██████████ ███ █████ ███████ ███████ ██████ ████ ████ ██████ ███ ███ ███████ ██ ███ ██████████ ██ ████ ████ ███ ███ ████ ██ ███████ ████ ███ ████████ ██ █████████ ███████ ████ ████████ ██████ █████████ ████████ █████████ ████ ████████████ ███████ ████ ████ ██████████ ██████ ███ █████ ██ ████████
"Surprising" Phenomenon
Health officials are certain that seafood contaminated with bacteria at a certain restaurant caused several cases of illness, but most people who ate seafood there didn’t come into contact with the offending bacteria.
Objective
The right answer will be a hypothesis that explains how health experts can be certain that contamination at that restaurant caused the illness, despite most people who ate seafood there not coming into contact with the bacteria. The explanation must tell us something more specific about why only certain people got sick.
21.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████ ███████████ █████████ ██████
a
Most people are ██████ ██ ███ ███████ ██ ███ ████████ ██ █████████
This doesn't explain how officials can be sure that bacteria at the restaurant caused this outbreak. If most people are immune, that might even undermine the claim that this bacteria was the cause of the sickness.
b
Those made ill ██ ███ ████████ ███ ███ ████ ██████ ██ █ ██████ ███ ████████████ ██████ ████
Did the waiter come into contact with the bacteria? Did the waiter get sick because of the bacteria, or for some other reason? Besides, we already know the bacteria was carried by contaminated seafood, so this isn't helpful.
c
All and only █████ ███ ███ ████████████ ███████ ██ ███ ██████████ ██ ████ ████ ████ ████████ ██ ███ ██████████ █████████ ██ █ █████ ████ ████ █████
This doesn’t explain why health officials are confident the bacteria was the problem. This simply gives another reason some people might’ve fallen ill.
d
The restaurant in ████████ ███ ████████ ████ █████ █ ███████ █████ ██████████ ██ ██████ ████████████
We already know the restaurant is serving contaminated food. We don’t need to double down. We need to explain how the officials can be so confident about the cause of the illness.
e
All and only █████ ███ ███ █ ██████████ ███████ ████ ██ ███ ██████████ ██████████ ███ ████████
Why did only some, but not all, people who ate seafood at the restaurant fall ill? Because those people who fell ill all ate a contaminated seafood dish that carried the bacteria. Other diners simply ate non-contaminated seafood, and were fine.