Self-study
Advertisement: Support Seventy-five percent of dermatologists surveyed prefer Dermactin to all other brands of skin cream. ████ ██ █████████ ██████████████ ██████ ███ ███████████ ██ █████████ ██ ██████ ████ ███ ████ ███ ████ ████ █████ ██ ███ ███████ ██ ██ ███ ████ █ ████ ██████ ███ ██████████
Summarize Argument
The advertisement concludes that you should use Dermactin if you need a skin cream. It supports this by saying that dermatologists were consulted during the development of Dermactin and 75% of dermatologists surveyed prefer Dermactin to all other brands.
Identify and Describe Flaw
The advertisement says 75% of surveyed dermatologists prefer Dermactin, but it doesn’t explain the details of the survey. They might have surveyed a small or biased group of dermatologists, which would make the results unreliable. Since the ad doesn’t say how many dermatologists were surveyed or if the survey was random, we can’t be sure that this survey actually supports the advertisement’s conclusion.
4.
The reasoning in the advertisement ██ ████████████ ███████ ███ █████████████
a
overlooks the possibility ████ █████ █████ ██ ███████ ████ █████ ██ ███ ██████████ █████ █████ ██████ ███ ██████ ████████████████
The sample may indeed be unrepresentative, but not because it fails to include other types of doctors. The argument is only based on the preferences of dermatologists; other types of doctors are irrelevant.
b
fails to state ███ ██████ ██ ██████████████ █████████ █████ ██████ ████ ███ ███████████ ████ ███ ██████ ██ ███████ ██ ███ █████ ██ ██ ████████
Because the ad doesn’t say how many dermatologists were surveyed, it’s possible that the sample size was too small. “75% of dermatologists surveyed” could simply mean 3 out of 4 dermatologists surveyed, which would mean the sample was too small and the survey is not reliable.
c
presumes, without providing ██████████████ ████ ████ ██████████████ ███ ████ █████████ ████ ██████ ██ ████████ ████ █████
Even if the ad did assume this, (C) doesn’t describe a flaw in the argument. Surely some dermatologists are less qualified to evaluate skin cream; this doesn’t change the fact that 75% preferred Dermactin.
d
relies on an █████████████ ██████ ██ ███ ████████ ██ █████████ ████ ██ ███████ █████████ ██ ████ ████
The ad relies on an appeal to the opinions of dermatologists who do have a special knowledge of skin care. It never mentions the opinions of consumers.
e
overlooks the possibility ████ ███ █ ███ ███████ █████ ██ ████ █████ ██ ██████████ ██ █████ ████ ███ ████ ████ █████
The ad doesn’t overlook this possibility. The conclusion says, “If you need a skin cream, use Dermactin.”