 And welcome back. Today what we're going to be doing is talking about the experimental probability. So this is a little bit different from the theoretical probability that you may use to be working with. Instead of what you want over total, experimental probability is the number of times the event occurred over your number of trials. So the big difference between theoretical and experimental probability is experimental probability actually uses data. It uses numbers from a chart or something to that effect rather than the theoretical possibility which deals with what could happen. Experimental probability deals more with what did happen. So go through this example real quick. The table shows the results of a spinner experiment. Find each experimental probability. So you took a spinner which had the numbers 1, 2, 3, and 4 on it, and you spun it a whole bunch of different times. You got six times you got a 1, 11 times you got a 2, 19 times you got a 3, and 14 times you got a 4. So it looks like three wins out right here. We get more threes than anything else. It looks like one kind of lost out. We don't get very many ones in this experiment. So this is what we want to do. We want to find the probability of spinning a 4. So the probability of spinning a 4 using experimental probability. Now again, instead of what we want over total, in this case, theoretical probability would be 1 over 4. The number of, sorry, the number 4 is the one that I want over a total of four numbers that I could get. That's theoretical probability, but we're not going to be using that. So what we're going to do is we're going to use experimental probability. We're going to use the number of times the event occurred over the number of trials. So in this case, 4's, how many times did the 4's occur? 4's occurred 14 times over a total of how many trials. Now to do this for the number of trials, what we have to do is we have to take all these occurrences and add them all together. 6 and 14 is 20. 11 and 19 is 30. So I got 20 and 30 to make a total of 50. So add those numbers together quickly. And then that would be, reduce that to 7 over 25. So the probability of spinning a 4 using this experimental probability is 7 out of 25 times. Now what you could also do is you could divide that and make that into a decimal. Decimal wise, that would be 0.28. Or you could say that this could be 28%. There's a couple of different ways you can write probability. Traditionally, we write them as fractions, but they can also be written as decimals or even percents. Sometimes, again, it depends on what the problem asks you to do. But at this level, if you're talking about experimental probability, you're probably pretty good at taking a fraction like this and making it into a decimal or a percent. You're pretty good at that. All right, second example here. Spinning a number greater than 2. So we're looking for the probability of spinning a number greater than 2. So I'm not going to write out that whole sentence. I can use just a little bit of notation. Maybe you have a variable in here to kind of shorten that up. So the probability of a number greater than 2. So again, we're going to take the number of events that occurred over the total number of trials. Well, I'm going to do the total number of trials. There was 50 total trials, 50 occurrences. Now I want the numbers that were greater than 2. In this case, my numbers greater than 2 are 3 and 4. So what I'm going to do is I'm going to take these occurrences of 3 and 4, and I'm going to add them together to get a total of 33. 33 is the number of events that occurred that I want. I want 3s. I want 4s. Those are the numbers that are greater than 2. So I have 33 of them over a total of 50 that occurred. And now there's no reducing that I have to do there. So that is my total probability. You can also write that as 0.66 or 66%. Either way, it works. So there's just a couple of examples of experimental probability. Now remember, the key difference between theoretical and experimental probability is the fact that experimental probability uses data. It uses a number. It uses a chart or a table or something to that effect, like what we have here. Whereas theoretical probability, totally different, you use the numbers that could happen. Or the total number of events or outcomes that could happen, as opposed to what actually did happen with experimental probability. Anyway, that's it for this video. Thank you for watching. Hope you enjoyed this. And we'll see you next time.