00:01
Hey folks, so we want to find the mean and the median to start off.
00:05
So what's the mean? well, we take kind of the, so we give, you know, if we randomly select a student, we want to know what is our kind of the expected value of their score.
00:17
So most of the, it looks like only one student score to zero, right? so what we're going to do is we're going to do zero times one over 20 because there's 20 students.
00:30
And so there's kind of the outcome times the probability of it happening.
00:36
Plus, okay, what is the other thing that can happen? we could select a student that has a score of 10.
00:43
And this would happen with probability, well, the probability of selecting one of the other 20 students, which is 19 over 20.
00:53
And, okay, so this altogether becomes, well, we can simplify the 10 and the 20 to get 19 halves, which is just a tiny bit smaller than 10, right? if all the students had scored 10, then the expected value would be 10.
01:11
Okay, the median score, this is just the data point that kind of lies in the middle, right? or you take the average of the two middle data points if you have like an even number of data points...