执行代码m[-c("poor","excellent","good","poor") ] patient[-factor(m) ] patient后,patient的因子水平下列说法正确的是（ ）
A: poor good excellent
B: poor excellent good poor
C: excellent good poor
D: 以上都不对
A: poor good excellent
B: poor excellent good poor
C: excellent good poor
D: 以上都不对
举一反三
- 执行代码m[-c("poor","excellent","good","poor") ] patient[-factor(m,order=TRUE,levels=c("poor","good","excellent"))) ] patient后,patient的因子水平下列说法正确的是（ ） A: poor good excellent B: poor excellent good C: excellent good poor D: 以上都不对
- If your English is neither very good nor very bad, which of the following word is the best one to describe it? A: excellent B: superb C: fair D: poor
- The good service at the hotel made up for the poor food to some ( ). The good service at the hotel made up for the poor food to some ( ).
- The properties of cast irons are as follows except . A: good castability B: poor mechanical properties C: good abrasion resistance D: poor machinability
- The good service of the restaurant ( ) the poor food to some extent.