Self-study
Some people think that in every barrel of politicians there are only a few rotten ones. ███ ██ ██████ ██ █ ███████ ██ ███████████ █ ███████ ███ █████████ ███████████ ███ ███████ ████ ████ ██ █████████ ██ █████ ██ ██ ███ ███ █████████ ███████ ███ ██ ████████████ ██████ █████ ███████ ███ █████ ██ ███████ ████ █████ ██ ██ █████████ ███████████
Summary
The stimulus can be diagrammed as follows:
Notable Valid Inferences
Effective politicians (i.e., politicians who do their jobs properly) are deceitful and not scrupulously honest. The contrapositive of this shows that if you’re scrupulously honest and/or not deceitful, you must not be an effective politician.
13.
Assuming that the author's statements ███ █████████ █████ ███ ██ ███ █████████ ██████████ ██████ ██ █████
a
Some people think ███ ███████████ ███ ███████
This could be true. The stimulus tells us that some people think there are a few rotten politicians. This implies some people do not think there are a few rotten politicians. Members of this latter group may think all politicians are rotten.
b
Some politicians are ████████████ ███████
This could be true. All we know is that effective politicians are not scrupulously honest—we don’t know anything about the character of ineffective politicians.
c
Some people define █ ████████████ ███ ██ ███████ ███ █████ ██ ████████
This could be true. We don’t know anything about how people do or don’t define a politician’s job.
d
Some deceitful politicians ███ ████████████
This could be true. We only know that all effective politicians are deceitful. We don’t know anything about ineffective politicians and whether or not they’re deceitful.
e
Some scrupulously honest ███████████ ███ ██████████
This must be false. The stimulus says that if you’re scrupulously honest you cannot be an effective politician. It is therefore impossible for there to be politicians who are both scrupulously honest and effective.