Sometimes you will be asked to draw conclusions without much data at all. The following question from
the calculator section has only one number in it, making the calculator pretty useless. Just stick to the facts
of the study and make sure not to take a conclusion too far.
14.When trees become iron deficient, their leaves will turn yellow prematurely. A botanist
is testing iron-doped fertilizers on maple trees with iron deficiencies. The botanist has
selected 200 maple trees in the state of Wisconsin that have been identified as having an
iron deficiency. Half of the trees are randomly chosen to receive the iron-doped
fertilizer, while the other half are given a fertilizer without iron. The results from the
test show that trees administered the iron-doped fertilizer had fewer premature yellow
leaves, indicating an increase in their iron levels. Which of the following statements
best describes the results of the test?
A) The iron-doped fertilizer will improve iron levels in any tree.
B) The iron-doped fertilizer reduces premature yellow leaves better than any
other fertilizer.
C) The iron-doped fertilizer will cause a significant increase in iron levels.
D) The iron-doped fertilizer will result in fewer premature yellow leaves in
maple trees in Wisconsin.Here’s How to Crack It
For this type of question, underline key words about how the study was conducted and what the study
found. In this case, the study was on 200 maples trees with iron deficiencies in Wisconsin, and the
conclusion is “The results from the test show that trees administered the iron-doped fertilizer had fewer
premature yellow leaves, indicating an increase in their iron levels.” Eliminate answers that don’t hit this
mark or go too far. In (A), it says that this treatment will help “any tree.” We are told only about “200
maples trees in the state of Wisconsin,” so we can’t draw conclusions about other trees. Eliminate (A). In
(B), the fertilizer used is compared to other fertilizers, which we also don’t know about. Choice (C)
sounds good, but it is hard to say what qualifies as “a significant increase in iron levels.” The statement in
(D) matches the key words you underlined perfectly without taking any aspect too far.