In an exploratory study, researchers discovered a strong negative corr

Question

In an exploratory study, researchers discovered a strong negative correlation between tree size and wood density for mature red spruce trees that were all about the same age. However, for groups of trees in which some trees were significantly younger than others in the group, the exploratory study did not find any correlation between tree size and wood density. Furthermore, trees with a higher wood density are stronger, more flexible, and able to survive more severe environmental conditions (such as drought or ice) than trees with lower wood density. In a subsequent study, the researchers will investigate whether this same relationship between tree size and wood density applies to the Siberian spruce.

Based on the information in the passage, select for  Strong negative correlation with wood density  a factor that has a strong negative correlation with wood density for mature red spruce trees of the same age according to the exploratory study. For  Control for , select a factor for which the information indicates the researchers in the subsequent study would need to control in order to determine whether the relationship between tree size and wood density identified in the exploratory study applies to the Siberian spruce. Make only two selections, one in each column.

GMATinsight · Answer

Sharin my Experience with this question:

I took 3 minutes on this question and made the right selection of choices

The tricky part was to choose the second choice which is a control variable (tree age) for the successive investigative study on tree of Siberian spruce

playthegame · Answer

Thanks, the question does give you a hint on how the age in one group played out or had no correlation for mature red spruce trees, interesting question, it took some time to read the question as the passage is wordy.

Thanks,

Thanks,

sayan640 · Answer

In an exploratory study, researchers discovered a strong negative correlation between tree size and wood density for mature red spruce trees that were all about the same age( control factor something which needs to be kept same ).

This sentence reveals all.

This sentence reveals all.

kendragoran · Answer

First answer is found here:  strong negative correlation between tree size and wood density
 
The second answer is not as straight forward, we need to look for the component that was different across the group of trees that were studied, that made a difference in the results: in this case, the age of the tree.

However, for groups of trees in which some trees were significantly younger  than others in the group, the exploratory study did not find any correlation between tree size and wood density.

Harsh_ · Answer

For 'Control for' : 
Tree size, Wood strength , Wood flexibility, The ability of trees to survive severe environmental conditions : Not the Answer - Depends on Wood Density and Wood Density cannot be controlled 
 Tree age : Answer - Does not depend on a Factor/ character of a Tree but on the Selection of Researchers doing the study

In an exploratory study, researchers discovered a strong negative corr

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Strong negative correlation with wood density	Control for
		Tree size
		Wood strength
		Wood flexibility
		Tree age
		The ability of trees to survive severe environmental conditions

GMAT Two-part Analysis (TPA) Questions

In an exploratory study, researchers discovered a strong negative corr

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