Exhibit 2 The following represents the probability dist……

单项选择题The student body of a large university consists of 60%female students.A random sample of 8 students is selected.What is the probability that among the students in the sample exactly two are female？（）

A.0.0896
B.0.2936
C.0.0413
D.0.0007

单项选择题A weighted average of the value of a random variable, where the probability function provides weights is known as（）

A.a probability function
B.a random variable
C.thee xpected value
D.random function

单项选择题A sample of 400 observations will be taken from an infinite population. The population proportion equals 0.8. The probability that the sample proportion will be greater than 0.83 is（）

A.0.4332
B.0.9332
C.0.0668
D.0.5668

单项选择题From a population of 500 elements，a sample of 225 elements is selected.It is known that the variance of the population is 900.The standard error of the mean is approximately（）

A.1.1022
B.2
C.30
D.1.4847

单项选择题Given the following information：Standar ddeviation=8 Coefficient of variation=64% The mean would then be（）

A.12.5
B.8
C.0.64
D.1.25

问答题在显著性水平α＝0.05时能否认为方案A和方案B在药品中转时间上存在差异？

问答题试求总体均值的置信水平为95%的置信区间。

问答题试求药品中转时间差异均值的点估计。

问答题解释回归系数的实际意义。

问答题当广告费用为10000时，销售量为多少？

问答题销售量与广告费用之间的相关系数是多少？

问答题销售量的变差中有多少是由于广告费用的变动引起的？

问答题若显著性水平α=0.05，检验3个生产商各自的应急照明灯的平均持续照明时间有无差异。

问答题完成下面的方差分析表：

问答题对＝α0.02，检验平均装配时间之差是否等于5分钟。