2020년도 수능영어 32번 예상문제

32. 다음 빈칸에 들어갈 말로 가장 적절한 것을 고르시오.

Regression to the mean was defined by Francis Galton in 1886 as “each peculiarity in a man is shared by his relatives, but on the average to a lesser degree.” His definition meant that a very tall man was likely to have shorter brothers and shorter sons and a very short man taller brothers and taller sons. The concept has been extended to describe the change in variables through time that results from selection at the start. Many examples of regression to the mean exist and a good example is provided when blood pressures are measured. Subjects with pressures initially higher than the mean tend to have lower pressures on the second occasion and those with starting lower blood pressures than the mean tend to be higher on the second occasion. Therefore, if you select a group of hypertensive patients on the basis of their high blood pressures, their measurements will certainly be lower on the second occasion owing simply to this regression-to-the-mean phenomenon. This fall in pressure and loss of repeatability should occur both in an actively treated and a control group and the provision of the control group will _________________________.                               *hypertensive 고혈압의 **regression 회귀

①undermine the effect of regression to the mean 

②lead researchers to a false conclusion 

③improve the credibility of the experiment  

④help the patients recover their normal blood pressure

⑤prevent the effect being ascribed to active treatment