Self-study
Medical researcher: As expected, Support records covering the last four years of ten major hospitals indicate that babies born prematurely were more likely to have low birth weights and to suffer from health problems than were babies not born prematurely. █████ ███████ ████ ████████ ████ ███████ ███ ███ ████████ ████████ ████████ ████ ████ ████ ██████ ██ ████ ███ █████ ██████ ██████ ████ ████ ███████ ███ ███ ████████ ██████████ ████████ █████ ████████ ████████ █████ ██████████ █████████████ █████████ ███ ████ ██ ███ █████ ██████ ███████
Summarize Argument: Phenomenon-Hypothesis
The researcher hypothesizes that adequate prenatal care significantly reduces the risk of low birth weight babies. This is supported by an observed correlation from hospital records: mothers who receive inadequate prenatal care are more likely to have low birth weight babies than mothers who receive adequate prenatal care. The records also noted that premature babies are more likely to have low birth weights.
Notable Assumptions
The researcher assumes that there is no alternative cause accounting for the observed correlation between inadequate prenatal care and low birth weight. For example, social or economic factors might instead cause both.
The researcher also assumes that the hospital records give a complete and accurate picture of the situation. If the hospitals’ data entry is flawed, then even the correlation may not be reliable.
24.
Which one of the following, ██ █████ ████ ███████ ███ ███████ ████████████ █████████
a
The hospital records ████████ ████ ████ ██████ ████ ███ ████ ████ ██████ █████ ███████ ███ ████ ██ ███████ ███ ███ ██████████ ████████ █████
Like (D), this does not weaken the researcher’s argument, because “many” normal birth weight babies being born despite inadequate prenatal care is totally consistent with an overall correlation between those factors. A statistic doesn’t require every individual case to match!
Illusory inconsistency
Illusory inconsistency
Answer is attractive because it seems to (but doesn't actually) contradict the premises or conclusion. In other words, it feints an attack on the premises or conclusion. If correlation is present, the answer choice is often merely an outlier datapoint, which is actually entirely consistent with the correlation.
b
Mothers giving birth ███████████ ███ █████████ ██████████ ██ █████████ ██ ██████ ████████ ██████████ ████████ ████ ████ ███ ██████ ██ ████ ████ ██ ███ ██████████
This weakens the researcher’s argument because it undermines the reliability of the hospital records. Premature babies usually have low birth weights, so this practice could easily skew the recorded correlation. And if the correlation isn’t solid, it’s hard to argue causation.
Alternate explanation
Alternate explanation
Weaken: Introduce or support an alternate explanation for a phenomenon.
Strengthen: Helps to eliminate an alternate explanation for a phenomenon.
c
The hospital records ████████ ████ ███ █████ ██████ ██████ ████ █████████ ██████████ ██ ██████ ████ ████ ████████████
This does not weaken the researcher’s argument because, unlike (B), it does not affect the correlation between low birth weight and inadequate prenatal care. If the researcher’s hypothesis was about premature birth and low birth weight, this might weaken, but it’s not.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
d
Some babies not ████ ████████████ █████ ███████ ████████ ████████ ████████ █████ ████ ███ █████ ████████
Like (A), this does not weaken the researcher’s argument, because the researcher is focusing on statistical trends, not individual cases. Even if “some” babies’ circumstances are different, that doesn’t mean the overall trend isn’t still reliable.
Illusory inconsistency
Illusory inconsistency
Answer is attractive because it seems to (but doesn't actually) contradict the premises or conclusion. In other words, it feints an attack on the premises or conclusion. If correlation is present, the answer choice is often merely an outlier datapoint, which is actually entirely consistent with the correlation.
e
Women who receive ████████ ████████ ████ ███ ████ ██████ ██ ████ █████ ███████████ ████ ███ █████ ███ ██ ███ ███████ ████████ ████████ █████
This does not weaken the researcher’s argument because it’s completely consistent with adequate prenatal care preventing low birth weight. In fact, this suggests an indirect causation where premature birth acts as a mechanism for causing or preventing low birth weight.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).