请问 为什么总体的分母自由度是N，不用减1呢？ 如果均值μ确定了 那自由变动的变量个数也是N-1 吧？

inventory valuation allowance 增加会影响cogs吗

The distribution of all the distinct possible values for a statistic when calculated from samples of the same size randomly drawn from the same population is most accurately referred to as:A.a discrete uniform distribution.B.a multivariate normal distribution.C.the sampling distribution of a statistic.老师讲一下这道题这几个选项呗

A population has a non-normal distribution with mean µ and variance σ2. The sampling distribution of the sample mean computed from samples of large size from that population will have:A.the same distribution as the population distribution.B.its mean approximately equal to the population mean.C.its variance approximately equal to the population variance.为啥A不对，大样本不是可以看成正态吗，为什么b对c不对

The best approach for creating a stratified random sample of a population involves:A.drawing an equal number of simple random samples from each subpopulation.B.selecting every kth member of the population until the desired sample size is reached.C.drawing simple random samples from each subpopulation in sizes proportional to the relative size of each subpopulation.老师AB为什么不对

这里公司 3 年期的另一只债券的风险溢价应该不等于 5 年期的风险溢价吧?这里要表达的意思是尽可能找 5 年期(与目标债券相同期限的),否则 3 年期虽然期限不同也可以使用是这样吗?

老师讲解一下这道题

存货减值，那cogs会增加吗，是减值算到cogs吗

罗伊第一比率越大越好吗？其中自己求的R是用获利除以自有资金？

A tree diagram is most likely used when dealing with investment problems that involve outcomes that are:A.mutually exclusive.B.independent at each node.C.unconditional at each node.老师这个二叉树哪个部分是无条件的哪个是独立的啊