The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year, as compared to last year. Health officials attribute this decrease entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease.
Which of the following, if true, would most seriously weaken the health official’s explanation for the lower incidence of the disease?
The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year, as compared to last year. Health officials attribute this decrease entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease.
Which of the following, if true, would most seriously weaken the health official’s explanation for the lower incidence of the disease?
The correct option is C Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.
Option (C)
Th health official’ s explanation assumes that the decrease in the number of people diagnosed with the disease accurately reflects a diminution in cases of the disease. By pointing out that this assumption is false, C undermines the official’s explanation and thus is the best answer. Since A supports the view that sanitary conditions have been improving, it tends to support the officials’ explanation. B also tends to support the officials’ explanation, because it eliminates a factor that might have differentiated between those contracting and those not contracting the disease and thus rules out an alternative explanation. The reduction of the severity of the diagnosed cases does not bear on the officials’ explanation. So D is not correct.
Option (C)
Th health official’ s explanation assumes that the decrease in the number of people diagnosed with the disease accurately reflects a diminution in cases of the disease. By pointing out that this assumption is false, C undermines the official’s explanation and thus is the best answer. Since A supports the view that sanitary conditions have been improving, it tends to support the officials’ explanation. B also tends to support the officials’ explanation, because it eliminates a factor that might have differentiated between those contracting and those not contracting the disease and thus rules out an alternative explanation. The reduction of the severity of the diagnosed cases does not bear on the officials’ explanation. So D is not correct.
