Self-study
Advertisement for a lactase supplement: Lactase, an enzyme produced by the body, aids in the digestion of lactose, a natural sugar found in dairy foods. ████ ████████ ██ ██ ██████████ ███ █████ █ █████ ██ ████ ██ ██ █████ ███████ ██████ █████ ██ ███████ ████████████████████████ ██ █████████ █████ ████████ ███████ ██ ████████████ ████████ █████ █████████████ ████ ███ ██████ ██ ████████ █████████ █████████ ██ █████ ██ ███████ ██████ ██ █████ ███████ █████ ██████ ████ ███████ ████████████
Summarize Argument
The advertisement claims that at least 50 million North Americans should take lactase supplements to help them digest dairy. How do we know? Well, in one study where participants drank a liter of milk on an empty stomach, a significant proportion had digestion troubles. By applying that proportion to the North American population, we get to 50 million.
Notable Assumptions
The advertisement assumes that drinking a liter of milk on an empty stomach accurately reflects people’s everyday dairy digestion needs. If people can generally handle smaller amounts of dairy just fine, then the study could be misleading.
The author also assumes that the sample group is equivalent to the general North American population—meaning that the participants weren’t unusually likely to be lactose intolerant.
21.
Which one of the following ███████████ ██ █████ ████ █████████ ███████ ███ █████████
a
Eating solid food ████ ████████ ████ ███ ████████ ███ ██████ ██ ███████ ████████ ██ ███ █████
This does not weaken the argument, We don’t know whether people normally drink milk while by itself or while eating food. If the former, then that makes no difference, because the participants weren’t eating. If the latter, then maybe even more people need lactase!
b
Most people who ███████ █████ ████████ ███████ ████ ███████ ██ ████ ████ ████ ███ ██████ █████ ██ █ █████ ██ █████
This weakens the argument by casting doubt on whether the study cited represents people’s normal dairy digestive needs. Maybe most people produce enough lactase for their usual dietary habits, even if a whole liter of milk at once would cause some problems.
c
The production of ███████ ██ ███ █████ ████ █████████ ████ ████
This does not weaken the argument because we don’t know anything about the age of the study participants, nor how that corresponds to the general population. If the participants were younger than average, that might be a problem, but we have no idea.
d
Lactose intolerance can █████████ ████ ██████ ██████████
This does not weaken the argument, because it doesn’t tell us anything about how representative the study was of the general population. Sure, lactose intolerant people should take lactase—but we still don’t know if that means 50 million people.
e
Some dairy foods, ████ ██ ███████ ███████ █ ████ ██ ███████ ████ █████████ ██ ██████ ████ ████ █████ ██ █████
This does not weaken the argument, firstly because we don’t know what kind of dairy people usually consume, and secondly because if anything it indicates a greater need for lactase than the study does. Either way, this doesn’t undermine the “at least 50 million people” claim.