There's also another variance measure, which we use in the sample-- There's also another variance measure, which is for the sample.
还有另一个离散指标,我们用以考察样本,这是另一个离散指标,用于考察样本
If you're comparing two portfolios with the same expected return, then you want the one with the lower variance.
比较两个有相同预期收益率的投资组合时,你会选择方差小的那一个。
So in return to, we have a slight variance here, -- where I'm defining apparently -- declaring a function called cube.
作为应答,这里我们有一点变化,这里我显然定义了-,声明了一个叫做cube的函数。
STUDENT: The variance of the Gaussian seems to be less than the variance of the uniform.
学生:高斯分布的变化比,均匀分布的变化小。
This portfolio, the minimum variance portfolio, is 9% oil, 27% stocks, and 64% bonds and most of the--many choices you can make.
这个最小方差的资产配置是9%的石油,27%的股票和64%的债券,而大部分。。。你可以有许多选择。
But, on the other hand, you don't want high variance because that's risk; so, both of those matter.
但另一方面,你不想要高水平的方差,因为它代表风险;,因此这两个参数都很重要。
In fact, I have it--suppose we have three assets and we want to compute the efficient portfolio frontier, the mean and variance of the portfolio.
事实上,假如我们拥有三种资产,我们想计算有效边界,及投资组合的均值和方差。
I'm not going to tell you what you want to do except to say, you would never pick a point below the minimum variance portfolio, right?
我不是教你怎样去组合,当然了,你不会选择一个,曲线上最小方差点以下的资产组合,对吧?
.. I started out with the equally-weighted-- I was talking about stocks-- about n stocks that all have the same variance and are all independent of each other.
开始的时候我讲了等权重的-,我开始时讲了股票-,几支拥有相同方差的股票,彼此间相互独立。
The variance of the Gaussian -- STUDENT: is less.
高斯分布的变化-,学生:更小。
The standard deviation is the square root of the variance.
标准差是方差的平方根
Depending on where the assets expected returns are and the assets' standard deviations, we can see that we might be able to do better than--have a lower variance than either asset.
根据资产的预期收益,以及收益的标准差,可以看到我们有更好的选择,这里的方差值比以上两种方案都要低。
Well if you're an investor, you don't like variance.
假如你是一个投资者,你不喜欢风险。
And in this context, the length of that array is stored in Arg C. Well, let's take a look at a slight variance of this that reveals further what we can do and reveals what a string really is.
关于这点,那个数组的长度被存储在ArgC中,好的,让我们看看这个轻微的变化,那个揭示了我们可以做的,和字符串实际上是什么。
What we did--the core theoretical framework that we had-- was the mean variance theory, which led us to the capital asset pricing model.
我们讲到了投资组合多元化的核心理论框架,即均值-方差模型,之后又讲到了资本资产定价模型
.. If you can find assets that all have-- that are all independent of each other, you can reduce the variance of the portfolio very far.
如果你能找到这样的一些资产-,一些相互独立的资产,就能很大程度上缩小这个投资组合的方差。
Oil, bonds, and stocks are all independent-- somewhat independent--they're not perfectly independent, but they're somewhat independent and, to the extent that they are, it lowers the variance.
石油,债券和股票都是互相独立-,一定程度上独立,不是绝对的独立,但一定程度上独立,可以使方差值变小,降低风险。
Expected value is good and variance is bad because that's risk; that's uncertainty.
期望值越高越好,方差就相反,因为方差代表着风险,也就是不确定性
I feel like I have to introduce concepts like variance and co-variance and correlation in order to talk about finance; so that's what we'll do in Lecture Two.
我会讲到像方差,协方差,相关系数,这样的概念,为金融学的内容作一些铺垫,我们会在第二课讲到
But, in between, if some other number, it'll be some blend of the--mean and variance of--the portfolio will be some blend of the mean and variance of the two assets.
但如果是在0和1之间的其他数值,这个投资组合的均值和方差将会是,两项资产各自的均值和方差的综合结果。
You'd have a higher expected return with no more variance.
你的预期收益率提高了,但风险没有增加。
But ultimately, everyone agrees I-- that's the premise here, that for the-- if you're comparing two portfolios with the same variance, then you want the one with the higher expected return.
但归根结底大家都会同意这一点-,这是一个前提-,当你比较两个有相同方差的投资组合时,你会选择预期收益率高的那一个。
The more x moves, the bigger the variance is.
参数的变动越多,方差就越大
They divide by n-1 to make it an unbiased estimator of the population variance, but I'm just going to show it in a simple way here.
当除以n-1表示的是对总体的,无偏估计,我在这里只是说的简单一点
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