Critical Reasoning

Studies have demonstrated that many immigrants to the United States receive excellent scores on the mathematics portion of standardized college entrance examinations. The high-quality mathematics education these people received in this country during their formative years is primarily responsible for this phenomenon.

Which of the following, if true, most seriously weakens the explanation above?
Immigrants who take standardized college entrance exams are not representative of the general population of immigrants, since only a small percentage of these people are college-bound.
Some educational experts are highly critical of the notion that standardized test scores can accurately indicate a student's level of college preparedness.
Average scores on standardized college entrance examinations have declined every year for the past two decades.
Because most immigrants are not native English speakers, their performance on the verbal portion of standardized college entrance exams is weak compared to that on the mathematics portion.
Immigrants who arrived in the United States after the age of 18 score just as high on the mathematical portion of standardized tests as those arriving at a very young age.

Hi,

Is the answer E

This option basically states that the high quality education is not responsible for immigrants succeeding in the mathematics portion of the standardized tests.

Regards
Anup

For weaken question, you have to chose an option that makes it likely that given conclusion is incorrect.

Argument concludes that high quality of education received in THIS country is responsible for high scores of immigrants. To weaken this statement, any of the following could work:
a) non-immigrant received same education but scores poorly
b) most of the immigrants came from asian countries and asians are known to be very good at mathematics

now as you keep evaluating the options, see e) is almost a paraphrase of the thought conveyed in above points.

One general tip for CR: many times when options are long sentences or when argument is confusing, GMAC tends to keep the correct option amongst D & E. GMAC wants people to panic by the time they read initial options and think that they are not getting hold of argument. To not to be be-fooled by this trap do 2 things: i) understand the argument ii) CALMLY evaluate options from a) to e), DON'T PANIC

Answer E says thats it must be in their gene or sth.. they didnt score well in Maths becoz they were taught well, but they somehow are born math genius..

While I was reading the passage and then read the question. One of the answers that I had prephrased in my head was that, immigrants who take those standardized test are the ones who are good at studies. Could this be a reasonable weakening answer?