四格表资料的卡方检验,其校正条件是()。
A.总例数大于40
B.有实际数为0
C.有实际数小于1
D.有一个理论数小于5大于1,且n≥40
E.两组例数相差较大
参考答案:D
Before leaving home, make sure to turn off the electricity, lock the door, ______ the windows open.
A.and not to leave
B.instead of leaving
C.rather than leave
D.and not leave
结肠癌肿块型哪一项是错误的
A.好发于左半结肠B.生长慢,转移晚C.易发生溃烂、出血D.不易引起肠腔狭窄及肠梗阻E.肿瘤向肠腔内生长,瘤体大