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Hi, hello. I am Cha Ling.
In the previous section, we finally talked about random variables. In probability theory and statistics, variance, standard deviation, etc. are used to describe the degree of dispersion of a random variable. So in this lesson, let's take a closer look at these concepts.
But before that, let’s take a look at what “mathematical expectation” is.
Mathematical Expectation
Mathematical expectations tell us what we can quantitatively expect from the results of a randomized experiment.
In other words, what kind of expectations can you have before the experiment is done? This is the origin of the term mathematical expectation.
For example, when we go to the gambling table, there are two outcomes when we gamble. The first outcome is to make a lot of money, with a return of 1,000 US dollars, but the probability is only 0.001. The second situation is that your $50 gambling capital is gone. The probability of this happening is very, very high, 0.999, which is 99.9%.