what are we looking at so this is a frequency table right it's a table that tells you about a particular kind of data in this case it's doctor's visits and how frequently those things happen right so these are different numbers of times that the doctor's been visited and this is the number of people who've visited the doctor that many times right so there are five people who didn't see the doctor at all in that whole I think it's a 3mon period okay there's six people who visited him once in that season and 14 people who and three people who and so on okay so frequency frequency is how many people or how many things have gotten this score right so this is number of visits it could be a test score it could be an amount of income it could be anything okay so let's have a March through this right you can see that we first want to know this is part A how many people survey so this is pretty easy get that's right all I need to work out is the people were this column here right frequency is um people so I'm just going to Total them up right let's just quickly go down 5 11 help me out 2 25 28 33 34 yep so that's just me adding up this frequency column 34 I think that's what I said okay so that's how many people are surveyed in total and that will come in handy when I working out um the mean later on cuz I've got to work out the average dividing by the total number of people the median how do I work out a median from this if there are 34 people in total right where's the middle of that do you remember we thought a little bit about this before yeah yeah you arrange the numbers in order okay so I want these in like you know ascending order I kind of already have an ascending order in that it's 0 1 2 Etc so that's really good okay but I need to know which score or scores are the median Nathan what would you suggest okay so a reasonable guess is here right like before I've even done any calculation cuz it seems like there's the most people there this kind of roughly in the middle but how would I be certain how would I go through a process where maybe the data is not so obvious any take is yeah Brandon what you do so B just cross okay yeah so you might remember if I had a set of scores like this 18 19 23 40 41 okay now obviously you can all see which one the meaning is cuz I've given you a nice small set but you could get there by Crossing off Crossing off Crossing off Crossing off and then what's left right and the only reason why that's a bit of a challenge here is because number one it'll take a while number two like these numbers might not match up nicely right the one and the five they don't match up do they um once I do this it's like oh I go a bit into here how far do I go in here do I it gets a little un clear okay so exactly right so here's what I'm going to suggest right do I have an odd number or an even number of scores have an even number of scores so if I have an even number of scores the median is not any particular score it's halfway between the two middle scores you see that okay so how do I know which ones are the two middle ones yeah you add three and four divide by two yep so once I've got these I'll take the average of those so what I want here right for six scores is between three and four for 34 scores I'm even going to write this down the median is between which two scores now to help you see six scores if I divide by two that's to get halfway right that gives me three and then I go one forward that gives me the next one okay so if I divide this by two I get 17 very good 17th score and the next one which will be the 18th score so now I can count now I can count and I don't have to worry about Crossing out or anything right so there's five there's 11 clearly the 17th score is going to be in here as we kind of anticipated right so 17th and 18th scores are both going to be here on two does that make sense cool now the mean okay so mean does anyone Remember by the way there's a symbol for mean does anyone remember it it's um an X with a little bar over it so sometimes you'll see that how do we work out the mean here's where we're going to need this extra column in here right see this is FX The Frequency multiplied by however many visits there were right so I'm going to have to multiply these numbers across to get the total number of visits that the doctor's gotten right so help me out 0 by 5 0 1 by 6 6 2 by 14 28 9 20 20 and okay fantastic so I want all the visits that the doctor has gotten so just like here I'm going to need to add these up okay has anyone already worked it out do it 6 3 71 71 uh 71 okay so that's how many times the doctors been visited all up so I can say 71 visits in total divided by what again how many people did those visits right so what do you get let's actually get like a decimal for that can we get you know like one decimal place maybe 2 point yeah good I'm getting um I'm getting 2.08 they haven't told us what to approximate so I'm just going to leave that as it is does that match what we expected yeah it does right like the vast majority of people have visited twice so that's why this number is kind of close to that it's a bit higher than two because you have all these people you even have a few people you have one person who's gone a whole load of times four times more than a normal person okay so we're almost finished now mode that's an easy one most common which one's got the most common it's it's this guy right because that's the most frequently noticed one so mode is also two and last one also simple question range is about top takeway bottom right so it's eight eight takeway zero eight take zero that's eight I think it's helpful as well to write down that it's Tak zero even though it doesn't change the number cuz that shows you know where range comes from it shows you know it's composed of these two numbers okay