【判断题】若E(XY)=E(X)E(Y),则X与Y独立.
【简答题】计算机不仅能进行复杂的数算,而且能对文字、图像和声音等进行处理,它是一种通用的______处理工具。
【判断题】若X,Y相互独立,其均值分别为E[X]与E[Y],则E[XY]=E[X]E[Y]。()
【单选题】What does the author think of teaching ability?
A.
It requires talent and practice.
B.
It is closely rela t ed to research.
C.
It is a ch i ef fac tor affecting students 'learning.
D.
It can b e ac qu i re d through pe r sistent practice.
【单选题】What does” the first basics of teamwork” refer to?
A.
The OOW works only person on the bridge
B.
The OOW has to follow the standing order
C.
The OOW calls watch stander a an lookout
D.
The OOW takes personally responsible for all aspects of rate navigation
【简答题】在sheetl工作表中建立如下内容工作表,并用公式求出每人的总评成绩,总评=平时 x30%+期末×70%,表中字体设为楷体16磅,数据水平居中,垂直居中,表标题合并居中、20磅、蓝色字,并将工作表命名为“成绩表”。 2. 将成绩表复制为一张新工作表,将期末成绩在80分到89分的人筛选出来,并将工作表命名为“筛选”保存在EX6.XLS中。
【单选题】若E(X)、E(Y)都存在,则下面命题中错误的是( )