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Scatter Plots & Bivariate Data

Added Oct 29, 2018 •

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write hello everybody today we are going to be talking about Scatter Plots and 5 Ariat data so first let's talk about bivariate data you know what data is data is just information now specifically data is numerical information its information in the form of numbers by means to and very it means variables so what is bivariate data bivariate data is numerical information concerning two different variables those two different variables might be height and weight and age and grade level they might be data about distance and time gallons or time in temperature or any two variables but whenever you have two variables and you have data about each of them we have what we call by very a day. Now I want to talk about the Orange County Fair when does the Orange County Fair I bet you have when you go to the Orange County Fair it's a little different than going to some other amusement parks because first you have to pay some money to get in the gate of the fair just to go there then once you're inside you probably want to go for some and each ride cost more money per ticket so let's say you pay $15 to get in the gates plus you pay $2 per ticket this isn't bivariate yet because the only variable number of tickets we bought but it really is bivariate because the other variable is the cost of going to the fair and the cost of going to the fair is dependent on another variable the amount of tick purchased so this is an example of by variate data now bivariate data loves to be displayed in a table like an input output table or we could put the dependent variable over here and the independent variable over here or we can take that bivariate data and display it on a graph bivariate data loves to be displayed on a graph as well so what say you what's the number to ticket on the x-axis and the number of dollars of cost on the y-axis and we start plotting some points for instance if you made no no tickets it's just 15 bucks in the door and you got it. There if you buy one ticket that's $2 more so that's 17 if you buy two tickets that's $4 on tickets plus the 15 to get in the door for a total of 19 and what we've got here is basically a bunch of bivariate data keep on going and going and going this by variant data happens to be perfectly linear but not all by variate data is for instance let's say you collected some bivariate data where your to bury temperature over time like let's say you woke up in the morning and it was 40 degrees then a little later it warmed up to 44 and then 250 and then to 54 but then it's kind of stayed 54 until it eventually started to cool off later that evening this would still be bivariate data even if it doesn't make a straight line because it's still data has to do with two variables time and temperature a lot of bivariate data by the way has to do with taking measurements over time so often you will see the x axis labeled with some kind of time measurement you heard a little bit about bivariate data answer these questions please what does the word data mean what does it mean and name two ways that you can display bivariate data okay now that you unpause the video we're going to move on to talking about Scatter Plots what is a scatter plot a scatter plot is when you plot some bivariate data. So let's talk height and weight no fat jokes because the height and weight that were talking about here is going to be little kids going to the doctor's office and getting their height and weight measured and it's not cool to make fun of little kids so let's say we put the right on the x-axis and the weight on the y-axis and we start measuring some kids so the first kid is 30 inches tall and 40 lb II kid is 40 in tall and fit the third kid is 40 in tall as well but we get some more kids of various Heights and weights throughout the rest of the day sometimes data isn't linear it's scattered all over the place so we talked about a scatter plot because the daughter kind of scattered all over the graph what's the point of making a scatter plot the point of making a scatter plot is that it gives you a picture of how the data is ranked so look at this we can understand the Bator the data better by seeing that it kind of goes in an upward trend and what that means in this situation is early as children grow taller they are by the pattern of the dots on the graph what's up with this kid well this kid is just special because they're tall there the second tallest kid but they're skinny there the third tallest or the third skinniest are third least weighty child that was measured this child is what we would call an outlier an outlier isn't bad it's just somebody that doesn't follow the Jen General trend of the rest of the data since this is abnormal compared to the rest of the day that it lies outside of the norm and we call it an outlier because it lies outside of the norm this kid so special and it's good to be different so be nice all right now when you have your scatter plot the dots make a pattern either going upwards or downwards or horizontally or vertically we call this correlation another word for correlation is Association and what we're saying is the two variables in question in this case height and weight are related to each other their Co related or their Associated so if the. Seem to kind of lineup in an upward Direction that's called positive correlation like positive slope on a positive correlation means that as one variable increases the other also increases and since most kids grow by gaining height and weight it makes sense that the state of would have positive correlation positive Association here's another example of positive Association or positive correlation if we kept track of the number of bacon cheeseburgers I eat and my cholesterol level as one goes up the other goes but that that is positive correlation if we keep track of the number of times I post inappropriate tweets about mr. petrilla probably positive correlation I guess anyways I think you get the idea so try to think of another two variables that might have positive correlation and then what do you think never negative correlation would look give me an example that's all we got for today thanks for listening and watching see you next time

Uploaded by Jeff Marbut.

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