某射击运动员在一次射击测试中射击6次,每次命中的环数为:7,8,7,9,5,6.则其射击成绩的方差为_____________.
题目分析:平均值为,
方差。
Man: I’m going to drop my Information Science class. It means too early in the morning. Woman: Is that really the good reason to drop the class, Tony Question: What does the woman mean
A. Tony should continue taking the course.B. She approves of Tony’s decision.C. Tony can choose another science course.D. She can’t meet Tony so early in the morning.
每班下班前,值班轮机员应将主机平均转速和海水温度告知值班驾驶员,值班驾驶员应回告本班()和风向风力,双方分别记入《航海日志》和《轮机日志》。
A、航速
B、航程
C、累积航程
D、平均航速