hey guys it's Mark from Ace tutors and in this video I'm going to explain a big foundational concept covered in statistics populations versus samples I'm first going to go over what each of these concepts are how they're different and then how they relate to each other with some examples okay so first what is a population well a population is every single person or thing or data point that belongs to a certain group for example a population might be every person that is a citizen of your home country or in another example a population might be every pair of pants that your company manufactures it can really be anything but the important thing to recognize is that the population is made up of every single thing that belongs to that group now let's quickly go over the various symbols and values that are used for a population throughout your class I'm sure you've seen a bunch of these symbols already the first thing to note is these are all called parameters because they correspond to a population we'll go through what the equivalent of these are for samples in a minute but let's quickly run through these ones first we have the Greek letter mu which is the symbol for population mean next p is the symbol for population proportion the Greek letter Sigma is the population standard deviation a capital N is the size of the population and finally the Greek letter row is population correlation coefficient I hope these look familiar but if some don't don't worry we'll be seeing a bunch more of these through future videos and examples all right now let's go over samples a sample is just a smaller subset of that larger population so for the example of citizens of a country a sample may be picking a thousand people from a certain area like the East Coast here or it might be picking a 100 people from every state Province or region or switching to the clothing company example it might be taking every pair of pants made on Monday or every fourth pair of pants that you made during the week there are tons of ways to pick a sample but the important thing to understand is that a sample is a subset of a population now let's bring back our population symbols and explain what the equivalent ones are for a sample similar to how all the values for a population are called parameters these values for a sample are all called statistics so let's quickly go through these just like we had mu to represent a population mean a sample mean is denoted by this symbol which we call xar because it has a little bar on top next a sample proportion looks like a P with a little hat on top which statisticians naturally called P hat after that we get a little more boring with s representing sample standard deviation lowercase n as the sample size and R as the sample correlation coefficient okay now that we went over populations and samples and how they're different let's quickly talk about how they're used Well normally when we use the different methods we learn in stats we usually want to figure out some information about our overall population as an example we might want to find the average income for people in our country or we might want to find what the average length of pants we manufacture however if our population is really really large it can be difficult to collect income data on every single person in our country or measure every single pair of pants that you make however with the magic of Statistics we don't have to instead of collecting data on everything in our population we can just collect data on a smaller subset of that population AKA a sample and use that information to figure out some pretty powerful information about our larger population in future videos we'll go over all the awesome things you can determine about a population just from some sample data but for now I hope you found this video helpful and if you did please hit that subscribe button to support us making more videos for you if you didn't please leave us a comment down below to let us know what we can do better thanks again for watching and remember you have big dreams don't let a class get in the [Music] way