一个样本的容量是80,分成若干小组画频数分布直方图,某组对应的频率是0.2,则该组有______个数据.
依题意,得该组数据=80×0.2=16,
故答案为:16.
女,65岁。头部摔伤3个月,头痛、呕吐1天。CT示左侧幕上新月形等密度病灶,中线移位。治疗首选()。
A.开颅血肿清除术
B.去骨瓣减压术
C.钻孔引流术
D.保守治疗
E.以上都不对
—______ of them knows Japanese, so I have to ask a third person for help.
―You’d better ask Tom for help. He is good at Japanese.
A.Neither
B.All
C.Both
D.None