Critical Reasoning

In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.

Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.

(B) In December of 1988, a new and far more accurate gas spectrometer was invented.

(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.

(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.

(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

my concern: i have a query regarding the answer. the proclaimed answer is B. and i can understand as how B cannot help to resolve this trend.

B says: In December of 1988, a new and far more accurate gas spectrometer was invented

reasoning as why B CANNOT help explain the trend: Choice B does not resolve because increased accuracy could mean detecting previously undetectable ozone and carbon monoxide particles OR it could mean a reduced rate of mistakenly identifying particles as ozone and carbon monoxide even though they are not ozone and carbon monoxide. On the former interpretation, the paradox is deepened while on the latter interpretation, the paradox is resolved.

HOWEVER i feel that the same reasoning can be put for option C and thus C might as well NOT HELP explain the observed trend.

C says: In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.----------->i feel that "THIS REVISING" could be done either way.let us say that earlier 10 units was "smog alerted" and the revised scale was brought to 5 units. in that case the trend CANNOT be explained; however, if the revised scale is revised to 15 units then the observed trend CAN be explained

my larger point is in question such as this in which we are asked to explain the trend DO WE NEED TO REJECT THE OPTIONS that can explain the "observed trend" either ways?

aditya8062 wrote:my concern: i have a query regarding the answer. the proclaimed answer is B. and i can understand as how B cannot help to resolve this trend.

B says: In December of 1988, a new and far more accurate gas spectrometer was invented

reasoning as why B CANNOT help explain the trend: Choice B does not resolve because increased accuracy could mean detecting previously undetectable ozone and carbon monoxide particles OR it could mean a reduced rate of mistakenly identifying particles as ozone and carbon monoxide even though they are not ozone and carbon monoxide. On the former interpretation, the paradox is deepened while on the latter interpretation, the paradox is resolved.

HOWEVER i feel that the same reasoning can be put for option C and thus C might as well NOT HELP explain the observed trend.

C says: In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.----------->i feel that "THIS REVISING" could be done either way.let us say that earlier 10 units was "smog alerted" and the revised scale was brought to 5 units. in that case the trend CANNOT be explained; however, if the revised scale is revised to 15 units then the observed trend CAN be explained.

Maybe this seeming issue can be resolved by noticing that while C does mention change that actually occurred in Los Diablos, B merely says that a new type of spectrometer was invented without saying that that type of spectrometer was put to use measuring the air quality in Los Diablos. In fact, for what this is worth, given that it was invented in December of 1988, it seems unlikely that it would have been put to practical use in a given city throughout the year 1989. So while both B and C could either resolve or deepen the paradox, as you said, B is more weakly connected to the situation in Los Diablos than is C.

aditya8062 wrote:my larger point is in question such as this in which we are asked to explain the trend DO WE NEED TO REJECT THE OPTIONS that can explain the "observed trend" either ways?

While I am not 100 percent sure, I would say that in a question involving choosing the least helpful, one should stick with choosing by determining the degree to which something explains something, and that following any other general rule might not work out.

In this case, for example, while C is not very helpful in explaining the change, B is even more weakly connected to the change, and thus B is the correct answer. So in this case sticking with that one strategy works and going beyond that strategy to eliminate answers by using further criteria does not.

Maybe this seeming issue can be resolved by noticing that while C does mention change that actually occurred in Los Diablos, B merely says that a new type of spectrometer was invented without saying that that type of spectrometer was put to use measuring the air quality in Los Diablos. In fact, for what this is worth, given that it was invented in December of 1988, it seems unlikely that it would have been put to practical use in a given city throughout the year 1989. So while both B and C could either resolve or deepen the paradox, as you said, B is more weakly connected to the situation in Los Diablos than is C.

I find this reasoning not correct.I will put my point
You are saying that there is a possibility that that they might not have been able to put it for practical use but then same argument can be put for option A .i might argue that for option A there might be a case when even though the rule were put in effect in dec 88 but still there result cannot be seen in 99 . My whole point is that if we want to create doubt then we can probably create doubt for any choice .

aditya8062 wrote:

Maybe this seeming issue can be resolved by noticing that while C does mention change that actually occurred in Los Diablos, B merely says that a new type of spectrometer was invented without saying that that type of spectrometer was put to use measuring the air quality in Los Diablos. In fact, for what this is worth, given that it was invented in December of 1988, it seems unlikely that it would have been put to practical use in a given city throughout the year 1989. So while both B and C could either resolve or deepen the paradox, as you said, B is more weakly connected to the situation in Los Diablos than is C.

I find this reasoning not correct.I will put my point
You are saying that there is a possibility that that they might not have been able to put it for practical use but then same argument can be put for option A .i might argue that for option A there might be a case when even though the rule were put in effect in dec 88 but still there result cannot be seen in 99 . My whole point is that if we want to create doubt then we can probably create doubt for any choice .

Yes, we can create doubt for any choice. I have to say I agree with your point. Maybe this question could be better written?

At the same time, as the question is written, it's the degree that matters. In this case, while one cannot be sure that other choices actually explain what happened, there is the least reason to suspect that C does.

That's my take anyway.