若设总体方差σ2=120，采用重复抽样抽取样本容量为10的一个样本，则样本均值的方差

绝缘电阻合格，带电部分与可触及导体之间的绝缘电阻Ⅰ类设备、Ⅱ类设备分别不低于( )。

A．2MΩ、5MΩ
B．2MΩ、7 MΩ
C．5MΩ、7MΩ
D．5MΩ、10MΩ

下列哪项不是造成铸件不完整的原因

A．铸道太细

B．铸圈温度过低

C．没有采用高频铸造机

D．合金熔化不充分

E．合金量不足

Whih of the following statements regarding the cerebrospinal fluid is FALSE

A．It is secreted by the choroids plexus

B．It bathes and nourishes the brain and spinal cord

C．It is composed mostly of protein with little sodium and potassium

D．It is resorbed by arachnoid villi

E．Blockage of its pathway leads to hydrocephalus

彩色暗室最好有（）

A.火炉

B.电扇

C.烘烤箱

D.空调及通风装置

在下面附属类方法中的下划线处应填入的正确参数是
public void writeData(______)throws IOException
GregorianCalendar calendar=new GregorianCalendar()；
calendar.setTime(hireDay)；
out.println(name+"|"+salary+"|"
+calendar.get(Calendar.YEAR)+"|"
+(calendar.get(Calendar.MQNTH)+1)+"|"
+calendar.get(Calendar.DAY_OF_MONTH))；

A．Employee[]e

B．"employee.dat"

C．PrintWriter out

D．BufferedWriter