here we want to find the mean and standard deviation of the following sample data now it's pretty easy to find the mean and standard deviation of sample data when you're given the data in a list format like this using the ti84 now there are multiple ways you can do this one you could go ahead and put all of this data into a frequency distribution because notice there are um data values that are repeated or you can just put it into the calculator the way it is we're going to do uh the ladder okay so what we're going to do is we're going to start by hitting stat and then edit and we will enter enter each of the data values individually in here and notice we will just go ahead and do 12.3 each time that it appears okay now when you're entering this stuff in make sure that you hit enter after each entry also if you have data in here and you don't want it you can um hit clear while highlighting the L1 or L2 if that's what you have Okay so let's say you put all the data values in then you're going to hit stat again then go over to Cal now see see the first thing says one VAR stats well that stands for one variable statistics which is what we are working with so you press enter well right now this is a function that your calculator will perform but you need to tell it what data values to perform that function on so we placed all of these data values in L1 so after we see one of our stats on our calculator we want to put L1 here so that it knows to perform the operation on L1 so we hit set second and then notice above the one key is L1 okay after we do that we press enter and we get lots of information here we get the mean which is represented by xar so the mean in this case is 11.55 now notice here there's an SX and a sigma X now because the sample and population standard deviation are going to be different there are two different values okay now because this was a sample we are going to use the one for sample so s is equal to 3.45 now if it had said population we would use the sigma X1 now even though there are two different variables for mean depending on whether it's a sample or population this is going to be the mean regardless of whether it is a sample or population now one thing that I always suggest to do is to check and make sure that this n is correct that there are exactly 10 data values that way you know that you entered everything um entered them all in um also you can scroll down and you can find other things like you can find the minimum and maximum data value and the core tiles from the data value so this is a very uh useful function in your calculator