all right we're going to do part two of our information on histograms we want to find we want to be able to locate our 25th percentile our q1 our median and our q3 in this histogram so that's interesting okay that's kind of a strange idea of trying to find that middle piece of data so let's talk about this if i want to find the middle piece of data in here then i need to know how many pieces of data there are so luckily this one has the numbers that are in each bin so i'm going to add all of those numbers up and get the total so i think i do that here um let's see so i total that's the first question how many total pieces of data are there in the set okay so how many pieces of data there's totaled them up and that's 403. okay so there we go 403 pieces of data all right now let's go through finding the median okay so the median is the middle piece of data so we think of the median as kind of like remember we want to divide by 2. so here's how i kind of find the piece of data that the median is i take 403 and i divide by two and because you know when we had small sets of data you would just kind of knock off the outside edges until you came to that middle well this is 430 pieces of data that's not going to work that great okay so we're we're going to have to do that a bit differently and so let's see 403 divided by 2 and that's going to be what 200 and one and a half 201.5 so 201.5 all right so if it comes out to be an odd number like that right if it's an odd number then what we do is we round up and that makes data piece number 202 is the median that's how that works okay so let's do that let's come up here and let's find it so here i go first number 36 okay then i got 54 more in the next one so i'm going to add 54. okay what is that i i'm adding correctly i think that that's 90 but then i'm always i'm always actually kind of bad at my adding and subtracting okay but those 34 plus 54 i think that's i'm up to 90 so far okay i'm still far away from this 202nd piece of data okay so then i'm going to add 69 and so far i'm at 90 plus 69 that's 159 okay so at this point i'm at 159 okay up to here i'm at 159 pieces of data all right so now let's see what happens when i add the next one in that's a 81. now it kind of looks like an 82. so if i took 159 plus this next 81 that's a lot that's way over 202 so that tells me that somewhere in this bar here is the 202nd piece of data so see i split it so there's 201 pieces of data down on the bottom data piece number 202 and then there's 201 pieces up on the top and that's how i get 400 so data piece number 202 and then the bottom 201 and the top 201 okay so i can tell then my median is in this bar here that looks like it's from 25 up to 30. remember it's not got 30s in there it's up 230 okay so that's what the value of my median is how many minutes practicing this daily practice minutes is the median time okay 25 minutes up to not including 30 minutes okay not including all right next the q1 okay so do you remember q1 is basically the median of this bottom half okay so look i got 201 pieces of data in the bottom half and that's what i ask here how many pieces of data are in the bottom half there's 201. okay which piece of data is the bod the middle of that bottom half okay we do like we did a minute ago 201 divided in half and that equals 100.5 so there we so now what we're gonna round up and what how did i write that here data piece okay we're going to round up and data piece number let's see data piece number what 101 is the not the median it's the median of the bottom half what's the median of the bottom half q 1. okay let's go find it okay so i'm looking for data piece number 101. here we go 36 plus 54 okay remember 36 plus 54 that equaled 90. okay that was 90. so that's not enough so i'm not there yet these ones here there's 90 i'm not there yet but remember if i added the 69 i got up here to 159 that's too much so where is my q1 somewhere in that bar so my q1 is from 20 up to 25 not including 25 so my q1 the 25th percentile is from 20 minutes up to not including 25 minutes all right now here's how i do my q3 i kind of take the easy cheaty way out instead of thinking from the median and add another 100 and however many up i i just do like the opposite instead of so i just take q1 we went from so we went up from the bottom to the 101st piece of data so you know what i'm going to do for q3 i'm going to go down from the top to the 101st piece of data so how many pieces of data from the top will be the location of data that is the q3 so 101 pieces of data from the top is q3 all right let's go find it here we go i'm going to count from the top okay i got here we go i'm gonna do this in another color um i got cute i got 17 okay i got to add these things up 17 plus that 21 or 22. i don't know i think that's 21. okay i don't think i'm there yet plus 25 okay so where am i add those up let's see where i'm at 17 plus 21 plus 25 i'm at 63. okay so that so so here these these bars here these ones here that brings that 63. okay remember i'm looking for 101 so i'm wondering what's going to happen when i add 43 more pieces of data well i can tell you where i'm actually i can tell you that one 63 plus 43 is going to be up to 106. so you know what that tells me my q3 is somewhere in that bar right there done so my q3 is from 35 up to but not including 40. so there we go my q3 was in what did i say 35 up to but not including 40. so 35 minutes up 2 but not including 40 minutes all right let's summarize it here we go what was our q1 our oh our q1 was this one 20 up to 25. okay there we go 20 up 2 25. what was our q our median our median was um what did we say our median the first one 25 up to 30. so the median is 25 up to 30 minutes okay context important i should have put that on here and then last what was our q3 we said 35 up to 40 minutes okay this is going to play into later when we start looking at histograms and we start looking at distributions and us needing to see if we have outliers okay we're gonna have to see if we've got outliers on those items all right and and come up with that so that's why we're doing this we want to in fact i probably should have told you that straight up at the beginning all right we want to come up see if we can calculate outliers well in order to do that we need to know these values all right here's the next one what do you notice is missing here look at these bars what's happening well i have not been told that specific total of each bar so i'm going to kind of have to make that up so i'm going to do that real quick so i'm going to say that this one's about looks like about four okay and then let's say what does this one look like that one looks like a little more than 25 so i'm going to say 26. since this one looks like it's about maybe 44 okay and so on so i want you take a moment go put those in there and then try this example too and i'll have another video and we'll check and see how you do all right let's see how you work that out