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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
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In an experiment, one thousand nine-year-old children were allowed to choose whether to participate in a program in which the researchers taught them dance during the daily break from their lessons. Four hundred of the children chose to participate for at least one year. At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not. The researchers hypothesized that dancing resulted in a sustained improvement in the children's sense of balance.

It would be most helpful in evaluating the researcher's hypothesis to know whether the researchers ___1___ prior to having __2__.

Select Researchers for the phrase that fills the blank labeled 1 in the given statement, and select Prior to for the phrase that fills the blank labeled 2 in the given statement to create the most accurate statement on the basis of the information provided. Make only two selections, one in each column.

1:Researchers | 2: Prior to
0 0 tested the children's ability to dance
0 0 designed a second experiment
0 0 divided the children into the two experimental groups
0 0 tested the children's sense of balance
0 0 taught dance to the children through the dance program

Hi, I found this question hard. In fact, not sure where to start with.
Can anyone explain this for me, please.

OA
1: tested the children's sense of balance
2: taught dance to the children through the dance program

For the first one i got it correct
but second i got stuck between c and e.

Even C fits perfectly.
Prior to divide into 2 experimental groups will tell me how children who had participated had significantly better balance, on average, than those who had not .

Since we are talking about sustained improvement are we going with E ?
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
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IMO, C is incorrect because, it implies that comparing the two groups is still the best way to conclude whether the dance lessons led to an improvement. However, this is not the best method, as it may be the case that students who took lessons (group A) did not improve, but those in the other group (group B) declined in their ability. Or, it may be that group A declined in their ability, but it was still far better to begin with. E is a good choice, because it directly determines whether dance lessons led to an improvement by only focusing on group A.
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
GMATNinja I was wondering if you could help me with this.

I have issues understanding why E is better than C.

First, were 400 students chosen, and out of those 200 were given lessons, and the rest didn't? Or were the 400 given lessons and the rest of the 1000 didn't? I don't see where in the passage we can fully deduce this.

Either way, if we are weighting the kids before splitting into the 2 groups, isn't that better than weighting them before the dance starts? I mean, it's the same really... because if you weigh them before diving them into experimental group, you also weigh them before dance starts... and the earlier you measure weight the better, since then you can avoid situations were... for example, students self select... so students who have better balance, sign up for the classes...! This you would not detect if you weight the students after you have already split the group into the two experimental groups.

I'm pretty confused. :S

In an experiment, one thousand nine-year-old children were allowed to choose whether to participate in a program in which the researchers taught them dance during the daily break from their lessons. Four hundred of the children chose to participate for at least one year. At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not. The researchers hypothesized that dancing resulted in a sustained improvement in the children’s sense of balance.
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
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gmat800live, I don't mind weighing in on this one... except that I'm not 100% sure that it's an official question. If it isn't, I don't think it's going to be worth anybody's time. Do you happen to know the source of the question? goodyear2013 posted this in 2014, so s/he might have stopped monitoring this thread a long time ago. :)
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
GMATNinja thank you so much! This was one of the questions I got wrong on GMAC official PrepTest 4! Definitely official :)!

GMATNinja
gmat800live, I don't mind weighing in on this one... except that I'm not 100% sure that it's an official question. If it isn't, I don't think it's going to be worth anybody's time. Do you happen to know the source of the question? goodyear2013 posted this in 2014, so s/he might have stopped monitoring this thread a long time ago. :)
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
Any clear reason why C is wrong for "prior"? Any experiment should have at minimum one treatment group and one control group. It's a requirement for validity sake.
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
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Think about this. The students CHOSE to dance. This causes bias. The people who chose to dance probably chose to because they wanted to. Maybe they danced before and therefore have better balance. So, checking their balance before the program will help understand what kind of boas was introduced which comparing results from before and after the dance lessons.
Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
GMATNinja
gmat800live, I don't mind weighing in on this one... except that I'm not 100% sure that it's an official question. If it isn't, I don't think it's going to be worth anybody's time. Do you happen to know the source of the question? goodyear2013 posted this in 2014, so s/he might have stopped monitoring this thread a long time ago. :)



Yes, I did get this in my Official GMAC Practice Test 4 too.
Please help [quote="GMATNinja"]

Thank you.
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
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gmat800live
GMATNinja I was wondering if you could help me with this.

I have issues understanding why E is better than C.

First, were 400 students chosen, and out of those 200 were given lessons, and the rest didn't? Or were the 400 given lessons and the rest of the 1000 didn't? I don't see where in the passage we can fully deduce this.

Either way, if we are weighting the kids before splitting into the 2 groups, isn't that better than weighting them before the dance starts? I mean, it's the same really... because if you weigh them before diving them into experimental group, you also weigh them before dance starts... and the earlier you measure weight the better, since then you can avoid situations were... for example, students self select... so students who have better balance, sign up for the classes...! This you would not detect if you weight the students after you have already split the group into the two experimental groups.

I'm pretty confused. :S

In an experiment, one thousand nine-year-old children were allowed to choose whether to participate in a program in which the researchers taught them dance during the daily break from their lessons. Four hundred of the children chose to participate for at least one year. At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not. The researchers hypothesized that dancing resulted in a sustained improvement in the children’s sense of balance.
gmat800live
GMATNinja thank you so much! This was one of the questions I got wrong on GMAC official PrepTest 4! Definitely official :)!

GMATNinja
gmat800live, I don't mind weighing in on this one... except that I'm not 100% sure that it's an official question. If it isn't, I don't think it's going to be worth anybody's time. Do you happen to know the source of the question? goodyear2013 posted this in 2014, so s/he might have stopped monitoring this thread a long time ago. :)
Hmm, the other funky thing is that the updated question only has 4 options, so the option (C) that you're talking about is no longer available. Does anyone have a screenshot to confirm the actual options from the test? NCC?

The deleted option ("divided the children into the two experimental groups") is suspicious because the researchers didn't divide the children into two groups. Instead, the 1,000 children were allowed to choose whether to participate (400 chose to participate, so those 400 children were taught dance during the daily break from their lessons).

Otherwise, yeah, the important thing is measuring their balance before the daily dance instruction began. So if we ignore the semantic issue with the (perhaps unofficial or altered) answer choice (C), it seems like either (C) or the final option could work.

You could argue that the final option speaks more directly to what's important (that the balance testing happened before the dance instruction), so even if neither is inaccurate, the last one is probably a bit better. But I'd love for someone to confirm the actual options before wasting too much time discussing an option that may not exist! :)
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
GMATNinja
gmat800live
GMATNinja I was wondering if you could help me with this.

I have issues understanding why E is better than C.

First, were 400 students chosen, and out of those 200 were given lessons, and the rest didn't? Or were the 400 given lessons and the rest of the 1000 didn't? I don't see where in the passage we can fully deduce this.

Either way, if we are weighting the kids before splitting into the 2 groups, isn't that better than weighting them before the dance starts? I mean, it's the same really... because if you weigh them before diving them into experimental group, you also weigh them before dance starts... and the earlier you measure weight the better, since then you can avoid situations were... for example, students self select... so students who have better balance, sign up for the classes...! This you would not detect if you weight the students after you have already split the group into the two experimental groups.

I'm pretty confused. :S

In an experiment, one thousand nine-year-old children were allowed to choose whether to participate in a program in which the researchers taught them dance during the daily break from their lessons. Four hundred of the children chose to participate for at least one year. At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not. The researchers hypothesized that dancing resulted in a sustained improvement in the children’s sense of balance.
gmat800live
GMATNinja thank you so much! This was one of the questions I got wrong on GMAC official PrepTest 4! Definitely official :)!

GMATNinja
gmat800live, I don't mind weighing in on this one... except that I'm not 100% sure that it's an official question. If it isn't, I don't think it's going to be worth anybody's time. Do you happen to know the source of the question? goodyear2013 posted this in 2014, so s/he might have stopped monitoring this thread a long time ago. :)
Hmm, the other funky thing is that the updated question only has 4 options, so the option (C) that you're talking about is no longer available. Does anyone have a screenshot to confirm the actual options from the test? NCC?

The deleted option ("divided the children into the two experimental groups") is suspicious because the researchers didn't divide the children into two groups. Instead, the 1,000 children were allowed to choose whether to participate (400 chose to participate, so those 400 children were taught dance during the daily break from their lessons).

Otherwise, yeah, the important thing is measuring their balance before the daily dance instruction began. So if we ignore the semantic issue with the (perhaps unofficial or altered) answer choice (C), it seems like either (C) or the final option could work.

You could argue that the final option speaks more directly to what's important (that the balance testing happened before the dance instruction), so even if neither is inaccurate, the last one is probably a bit better. But I'd love for someone to confirm the actual options before wasting too much time discussing an option that may not exist! :)

I just did Prep4 today, chose C (divided...two experimental groups), got that wrong, which is what brought me here. So yeah option C definitely exists.

My understanding (after I got it wrong) is that you don't really have to measure the baseline balance scores BEFORE splitting subjects into groups. Even after splitting the subjects into groups, and then through measurements it is found that the baseline balance of the "dance" group is higher, you can still claim the effect of dance on balance by comparing incremental improvements between dance/control groups.
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
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­Understanding the Argument
In an experiment, one thousand nine-year-old children were allowed to choose whether to participate in a program in which the researchers taught them dance during the daily break from their lessons.
  • Experiment: children given the choice to participate in dance tutoring

Four hundred of the children chose to participate for at least one year.
  • 400 (out of 1000) chose to participate for at least 1 year.
  • The remaining 600 did not.

At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not.
  • This option compares the children who had participated in the program (those 400 children) and the children who hadn’t participated in the program (those 600 children)
  • Interestingly, the basis of comparison is not the ability to dance, which they were taught. The basis of comparison is how much balance children had. (If you are not reading the passage carefully, you may end up assuming that the comparison is about the ability to dance.)
  • Those 400 children had much better balance, on average, than those 600 children.

The researchers hypothesized that dancing resulted in a sustained improvement in the children's sense of balance.
  • The hypothesis is that dancing caused improvement in children’s sense of balance.
  • The hypothesis is supported by the previous observation that the children who had participated in dance tutoring (and thus danced) had better balance than the children who had not participated in dance tutoring (and thus perhaps did not dance).
 
 Gaps in the Argument
I can see that this argument is a typical correlation-to-causation argument in which the premise is a correlation between dancing and balance, and the conclusion is a causation statement that dancing caused better balance.

Besides, we don’t even know whether the 600 children (who didn’t participate in the program) danced less during the year than the 400 children who participated. It is possible that those 600 children danced more through other programs or on their own.
Understanding the Question Stem
It would be most helpful in evaluating the researcher's hypothesis to know whether the researchers 1 prior to having 2.

We’re trying to evaluate the researcher’s hypothesis and looking for options that will fit into the blanks to help us evaluate the hypothesis.

The first blank will be something like WHAT RESEARCHERS DID prior to having DONE SOMETHING ELSE

Together, the statement created with the filled blanks will help us evaluate the researchers’ hypothesis.

Select Researchers for the phrase that fills the blank labeled 1 in the given statement, and select Prior to for the phrase that fills the blank labeled 2 in the given statement to create the most accurate statement on the basis of the information provided. Make only two selections, one in each column.
Evaluating the Options

A. tested the children's ability to dance
  • It’s a very tempting choice for people who didn’t read the passage carefully.
  • Even though the argument talks about teaching dance, it is NOT CONCERNED about the children’s ability to dance.
  • The argument talks ONLY about the sense of balance caused by dancing.
  • Researchers’ testing the children’s ability to dance WILL NOT help us evaluate the argument about whether dancing helps children become balanced.

B. designed a second experiment
  • How will we evaluate the argument by knowing that the researchers designed a second experiment WITHOUT KNOWING how the experiment will help us evaluate the argument.
  • Of course, a helpful experiment can be created to evaluate the argument.
  • However, the option doesn’t say that experiment will help us evaluate the argument in any way.
  • The option talks only about designing a second experiment.
  • Designing a second experiment in itself will not help.

C. tested the children's sense of balance
  • Testing the balance makes sense since this argument is about whether dancing builds children’s sense of balance.
  • However, to select this option for the first part, I need to find the appropriate second part.
  • So, I’ll keep this on hold while I look at the other options.

D. taught dance to the children through the dance program
  • We know that the researchers taught dance to children through the dance program
  • So, this part may fit in the second label.
  • Let’s read C and D together → Researchers tested the children's sense of balance prior to having taught dance to the children through the dance program.
  • In this case, researchers will have data about the balance of childrens in two groups.
  • If the group that did not participate had better or the same balance before the dance program, then the argument would be strengthened. (After the program, we’re given that the children who participated in the program had better balance. Thus, in this case, we’ll believe more in the idea that the program (or dancing) bettered the children’s sense of balance.)
  • If the group that did not participate had a worse balance before the dance program, then the argument would be weakened. In this case, the group that participated in the dance program had better balance to begin with. So, we cannot say that dancing bettered their balance.
­­­­­
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
GMATNinja
gmat800live
GMATNinja I was wondering if you could help me with this.

I have issues understanding why E is better than C.

First, were 400 students chosen, and out of those 200 were given lessons, and the rest didn't? Or were the 400 given lessons and the rest of the 1000 didn't? I don't see where in the passage we can fully deduce this.

Either way, if we are weighting the kids before splitting into the 2 groups, isn't that better than weighting them before the dance starts? I mean, it's the same really... because if you weigh them before diving them into experimental group, you also weigh them before dance starts... and the earlier you measure weight the better, since then you can avoid situations were... for example, students self select... so students who have better balance, sign up for the classes...! This you would not detect if you weight the students after you have already split the group into the two experimental groups.

I'm pretty confused. :S

In an experiment, one thousand nine-year-old children were allowed to choose whether to participate in a program in which the researchers taught them dance during the daily break from their lessons. Four hundred of the children chose to participate for at least one year. At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not. The researchers hypothesized that dancing resulted in a sustained improvement in the children’s sense of balance.
gmat800live
GMATNinja thank you so much! This was one of the questions I got wrong on GMAC official PrepTest 4! Definitely official :)!

GMATNinja
gmat800live, I don't mind weighing in on this one... except that I'm not 100% sure that it's an official question. If it isn't, I don't think it's going to be worth anybody's time. Do you happen to know the source of the question? goodyear2013 posted this in 2014, so s/he might have stopped monitoring this thread a long time ago. :)
Hmm, the other funky thing is that the updated question only has 4 options, so the option (C) that you're talking about is no longer available. Does anyone have a screenshot to confirm the actual options from the test? NCC?

The deleted option ("divided the children into the two experimental groups") is suspicious because the researchers didn't divide the children into two groups. Instead, the 1,000 children were allowed to choose whether to participate (400 chose to participate, so those 400 children were taught dance during the daily break from their lessons).

Otherwise, yeah, the important thing is measuring their balance before the daily dance instruction began. So if we ignore the semantic issue with the (perhaps unofficial or altered) answer choice (C), it seems like either (C) or the final option could work.

You could argue that the final option speaks more directly to what's important (that the balance testing happened before the dance instruction), so even if neither is inaccurate, the last one is probably a bit better. But I'd love for someone to confirm the actual options before wasting too much time discussing an option that may not exist! :)
 Sajjad1994 , the official question (OG23-24) does infact contain option-C. Could you make the changes please in the question here? Thanks! 

 GMATNinja wanted to confirm that option-C does infact exist. Also, do you reckon that E is better than C, since we want to know strictly the effect of only the dance training period on their balance (since that is what the hypothesis entails), and that C includes an additional time-period (although possibly small), that might involve factors outside dancing affecting their balance. (example - after choosing to go in the dancing group, some students practice their balance skills which improves their skills, but it isn't strictly due to dancing.)

­
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PReciSioN
 Sajjad1994 , the official question (OG23-24) does infact contain option-C. Could you make the changes please in the question here? Thanks! 

 GMATNinja wanted to confirm that option-C does infact exist. Also, do you reckon that E is better than C, since we want to know strictly the effect of only the dance training period on their balance (since that is what the hypothesis entails), and that C includes an additional time-period (although possibly small), that might involve factors outside dancing affecting their balance. (example - after choosing to go in the dancing group, some students practice their balance skills which improves their skills, but it isn't strictly due to dancing.)

­
­
Added the option. FYI, the two part analysis questions can have 5 or 6 options only.­
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GMATNinja
Hmm, the other funky thing is that the updated question only has 4 options, so the option (C) that you're talking about is no longer available. Does anyone have a screenshot to confirm the actual options from the test? NCC?

The deleted option ("divided the children into the two experimental groups") is suspicious because the researchers didn't divide the children into two groups. Instead, the 1,000 children were allowed to choose whether to participate (400 chose to participate, so those 400 children were taught dance during the daily break from their lessons).

Otherwise, yeah, the important thing is measuring their balance before the daily dance instruction began. So if we ignore the semantic issue with the (perhaps unofficial or altered) answer choice (C), it seems like either (C) or the final option could work.

You could argue that the final option speaks more directly to what's important (that the balance testing happened before the dance instruction), so even if neither is inaccurate, the last one is probably a bit better. But I'd love for someone to confirm the actual options before wasting too much time discussing an option that may not exist! :)
 Sajjad1994 , the official question (OG23-24) does infact contain option-C. Could you make the changes please in the question here? Thanks!

GMATNinja wanted to confirm that option-C does infact exist. Also, do you reckon that E is better than C, since we want to know strictly the effect of only the dance training period on their balance (since that is what the hypothesis entails), and that C includes an additional time-period (although possibly small), that might involve factors outside dancing affecting their balance. (example - after choosing to go in the dancing group, some students practice their balance skills which improves their skills, but it isn't strictly due to dancing.)­
­Thanks for the confirmation!

You make a good point -- maybe the students who signed up for the dance class decided to do some balance training in preparation for the course.

Another issue with (C) is that it implies that the scientists DIVIDED the students into two experimental groups: that's not quite accurate, since the students were allowed to choose. 

Even if you think (C) is fair game, (E) is a better answer, since, as we stated earlier in the thread, it speaks more directly to what's important: the balance testing happened before the dance instruction.

In short, there are a couple not-so-great reasons to pick (E) over (C), but there are NO good reasons to pick (C) over (E). So (E) is our winner. 

I hope that helps! ­
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Re: In an experiment, one thousand nine-year-old children were allowed to [#permalink]
KarishmaB ChiranjeevSingh

Can you please help me understand why C is incorrect?
c) divided the children into the two experimental groups

It would be most helpful in evaluating the researcher's hypothesis to know whether the researchers ___1___ prior to having __2__.

I'm not convinced with the reasoning that researcher didn't divide the group and children choose the dance, hence it is not relevant.

I think even if children choose to dance, the option "divided the children into the two experimental group" can be helpful in evaluating the hypothesis. The researcher divided the group to understand the increase of balance between 2 groups.
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goodyear2013
In an experiment, one thousand nine-year-old children were allowed to choose whether to participate in a program in which the researchers taught them dance during the daily break from their lessons. Four hundred of the children chose to participate for at least one year. At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not. The researchers hypothesized that dancing resulted in a sustained improvement in the children's sense of balance.

It would be most helpful in evaluating the researcher's hypothesis to know whether the researchers ___1___ prior to having ___2___.

Select Researchers for the phrase that fills the blank labeled 1 in the given statement, and select Prior to for the phrase that fills the blank labeled 2 in the given statement to create the most accurate statement on the basis of the information provided. Make only two selections, one in each column.­

ID: 100307

­
­
It is simply a CR question based on "studies conducted" testing a concept we have seen tested often in CR.

In an experiment, 1000 children were allowed to choose whether to participate in a program in which the researchers taught them dance. 400 chose to participate. At the end of the year, researchers found that the children who had participated had significantly better balance, on average, than those who had not.

Conclusion: Dancing resulted in a sustained improvement in the children's sense of balance.


What is our problem here? That the children were given the choice. What if children who choose to dance are the ones who naturally have better balance? Because of their better balance, they enjoy dancing more and do a better job at it and hence they feel like dancing. Basically, when we are comparing two groups, the groups must be unbiased samples, they must be equivalent. Here they are not.

Had the researchers instead taken two unbiased groups of children which were fair representaion of the population and then made one group dance, there was a better chance of proving the point.

Hence testing the groups for their balance before the dance sessions was important - to know whether both groups represent the population fairly or whether one group has naturally better balance than the other.

Also, there is a natural, automatic division of the groups here - those who wanted to dance and those who did not. There is no question of researchers dividing into two groups.­
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