Hi Munda,
Just a try.
conclusion says: the two types of memory loss are qualitatively different
Evidence : ineffective drug on other population group with brain damage due to injury.


Assumption: there is no other thing that is different in the population sample.

E says that the age was different that weakens the argument by pointing out other factors that might be responsible for the difference in the result

B says that memory loss prior to the treatment was same. This statement validates that both the population does not have different amounts of memory loss.
If both group have different amount of memory loss then It can be argued that it is difference in the memory loss amount not the qualitative difference that is responsible for ineffectiveness of drug.

hI pEARL_rafter

Couldnt there be more than 1 assumption


Assumption: there is no other thing that is different in the population sample.
If you have been thru powerscore CR , you must have come across the concept of 2 types of Assumptions
1)Defender Assumption : An assumption that precludes the occurence of any event that weakens the argument
2) I forgot the exact terminology for this type but it works by bridging the gap between the premise and the conclusion
The assumption that you stated is a kind of Defender Assumption .
Doesnt E (IMO the second type of Assumption ) reinforce the link between the premise and the conclusion

To strengthen the conclusion we must prove that the test conducted is not biased by any other conditions. In option E the avg age is different. Now with the option E we can as well argue that "it is not the type of memory loss but the age which decides the effectiveness of the medicine".

mundasingh123 wrote:
I wish to resolve my doubt . So i am addressing this post to an expert
Hi David/Ron /Brian/GmatGuruNY / any other expert
E says that the average age of the people suffering from alzeimers disease was higher than that of people suffering from injury induced memory loss. This tells us that mechanism by which alzheimers disease causes memory loss may be different from the mechanism by which injury causes memory loss . This strengthens the argument too .
Is this Logic so unreasonable ?

Two reasons to eliminate E.

E discusses a difference in AGE between the two groups.
Thus, E could WEAKEN the conclusion by implying that it wasn't the TYPE of memory loss (Alzheimer's vs. brain injury) but the AGE of the two groups that caused the drug to have different effects.

Be skeptical of AVERAGES.
Answer choice E states only that the AVERAGE age of the brain injury group was less than the AVERAGE age of the Alzheimer's group.
It could be that EVERYONE in the brain injury group is 50 years younger than EVERYONE in the Alzheimer's group.
It could be that everyone in the two groups is of the SAME age except for ONE person in the brain injury group who happens to be just ONE YEAR younger than everyone else.
Thus, information about the average age of each group is of limited value.

Thank You GmatGuruNY . Could you also give an example of a strengthener that bridges the gap between the premise and the conclusion in this argument .

mundasingh123 wrote:Thank You GmatGuruNY . Could you also give an example of a strengthener that bridges the gap between the premise and the conclusion in this argument .

Everyone in the study was of roughly the same age.

This answer choice would RULE OUT age as a possible cause, strengthening the conclusion that the TYPE of memory loss caused the drug to have different effects.

Whereas those who suffer memory loss due to an injury cannot recall events from long ago, those who suffer memory loss due to Alzheimer's cannot recall events that are more recent.

This answer choice would confirm that the two types of memory loss are QUALITATIVELY different.

GMATGuruNY wrote:

mundasingh123 wrote:Thank You GmatGuruNY . Could you also give an example of a strengthener that bridges the gap between the premise and the conclusion in this argument .

Everyone in the study was of roughly the same age.

This answer choice would RULE OUT age as a possible cause, strengthening the conclusion that the TYPE of memory loss caused the drug to have different effects.

Whereas those who suffer memory loss due to an injury cannot recall events from long ago, those who suffer memory loss due to Alzheimer's cannot recall events that are more recent.

This answer choice would confirm that the two types of memory loss are QUALITATIVELY different.

This was very helpful ,gmatguruny