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by vaivish » Fri Jul 25, 2008 12:40 am
13. Five years ago, during the first North American outbreak of the cattle disease CXC, the death rate from the disease was 5 percent of all reported cases, whereas today the corresponding figure is over 18 percent. It is clear, therefore, that during these past 5 years, CXC has increased in virulence.
Which one of the following, if true, most substantially weakens the argument?
(A) Many recent cattle deaths that have actually been caused by CXC have been mistakenly attributed to another disease that mimics the symptoms of CXC.
(B) During the first North American outbreak of the disease, many of the deaths reported to have been caused by CXC were actually due to other causes.
(C) An inoculation program against CXC was recently begun after controlled studies showed inoculation to be 70 percent effective in preventing serious cases of the illness.
(D) Since the first outbreak, farmers have learned to treat mild cases of CXC and no longer report them to veterinarians or authorities.
(E) Cattle that have contracted and survived CXC rarely contract the disease a second time.

OA is D
Source: — Critical Reasoning |

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by reply2spg » Wed Aug 11, 2010 8:10 am
What is wrong with C
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by thephoenix » Wed Aug 11, 2010 8:39 am
IMO it's a typical number/percentage type CR if u have a power score CR just go through the chapter and then resolve it
however my take is the correct ans is the one for such problems which brings in the fact that there is some error with the numbers.
if in first outbreak no. of cases were 5000 and all were reported then actual death were 250(5% of 5000)
and if suppose 360 deaths happened in recent outbreaks out of 2000 reported cases then indeed % of deaths > then 1st outbreak, however if another 2000 cases, which are not reported as said by option D then the figure would have been 9% , a figure lower then prev.
Hence option D weakens it
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by arora007 » Wed Aug 11, 2010 9:05 am
vaivish wrote:13. Five years ago, during the first North American outbreak of the cattle disease CXC, the death rate from the disease was 5 percent of all reported cases, whereas today the corresponding figure is over 18 percent. It is clear, therefore, that during these past 5 years, CXC has increased in virulence.
Which one of the following, if true, most substantially weakens the argument?
(A) Many recent cattle deaths that have actually been caused by CXC have been mistakenly attributed to another disease that mimics the symptoms of CXC.
(B) During the first North American outbreak of the disease, many of the deaths reported to have been caused by CXC were actually due to other causes.
(C) An inoculation program against CXC was recently begun after controlled studies showed inoculation to be 70 percent effective in preventing serious cases of the illness.
(D) Since the first outbreak, farmers have learned to treat mild cases of CXC and no longer report them to veterinarians or authorities.
(E) Cattle that have contracted and survived CXC rarely contract the disease a second time.

OA is D
As soon as you see "5 percent of all reported cases"
"today the corresponding figure is over 18 percent"

the thought crosses the mind... what if... in the earlier days...reporting was less...
searched for the word "report" and had a looked if it fits in... yes it did... I then just had a cursory look at other choices..to rule them out... just about a minute to solve....

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