Current location - Training Enrollment Network - Mathematics courses - Ask God to explain the contents of "expectation" and "expectation value" in mathematics (probability)
Ask God to explain the contents of "expectation" and "expectation value" in mathematics (probability)
Expectation is the weighted average of possible results to probability, but it is not necessarily the average.

Give a simple example:

When buying lottery tickets, there is a 20% chance of winning 10, a 30% chance of winning 5, and a 50% chance of not winning.

What is the expectation of the money you can get?

Expected value = 20% *10+30% * 5+50% * 0 = 2+1.5+0 = 3.5, which means you can expect to get 3.5 yuan when you buy lottery tickets.

For a lottery ticket, you may not understand this 3.5, but if you buy/kloc-0.0 million lottery tickets and divide all the money in the lottery ticket by/kloc-0.0 million, the answer will be very close to 3.5, which is the meaning expressed by the expected value.

In other words, if the probability of all three cases is one-third, then the process of finding the expected value is the same as that of finding the average value.