statistics Learning Center presents graphical representation of data hi I'm Dr Nick and in this video I'm going to explain briefly about seven different types of graph I'm going to talk about when each of the seven graphs is used and some things to be aware of there are other ways to display data such as tables but this video is about graphs the whole point of Statistics is that when we get data from multiple objects or people we can find out more than we can with one individual piece of data we can use data to answer questions when we have a lot of data it can be difficult to see patterns in it just by looking at the numbers but by drawing a graph we can get an idea of the distribution of the data we can use the graph to analyze the data to answer questions and to communicate our findings pictograph the simplest form of of graph involves lining actual objects up in rows according to characteristics for example we may be interested in what fruit students bring for a class fruit salad we can line the pieces of fruit up on a table according to type it makes it possible to answer questions like what is the most popular fruit for a fruit salad and have people brought more bananas than Apples it's fun to use real objects but mostly in pictographs we used pictures of the objects these pictures should make sense with the context another type of pictograph uses data cards each card shows the data for one individual person or thing this pictograph shows us that we have more dragons that breathe ice than breathe acid fire or nothing special the data for a pictograph is categorical we are counting instances of a characteristic not measuring any anything bar chart this is also sometimes called a column chart the data we showed in the pictographs can also be represented in a bar chart in a bar chart the length or height of the bar represents the number of times that object occurs or the frequency on bar charts it is easy to see which category is the biggest even when there is little difference we can order the categories by size to give more information B charts can be used for categorical data and for some numerical data pie charts pie charts are popular with nonstatisticians the area of each segment of the circle or Pi represents the proportion for each of the categories it is only acceptable to use a pie chart if you have five or fewer categories and the data is categorical and does not have an inbuilt order to to it and you keep the graph simple no 3D and absolutely no exploding people like pie charts but they are only good in a few circumstances dot plots now dot plots are really useful dot plots are used for numerical data each dot represents one data point in this Dot Plot of heights each dot corresponds to one Dragon dot plots are like number lines but with the dots stacked up when there is more than one object that has the same value this Dot Plot shows the number of pairs of shoes different people said they owned each dot represents one person dot plots are great for getting an idea of the shape of the distribution of the data mostly we use computers to make dot plots this is a very good applet you can use for free stem and leaf plots stem and leaf plots are great for getting a quick idea of the shape of the data the stem is the first digit of the number and the leaf is the second digit this stem and leaf plot is of the grades a class of students got in a test out of 100 you can see that one person got 14 one person got 20 and one got 22 scatter plot skatter plots are used for showing the relationship between two numerical variables each dot represents one observation or thing in this case each dot represents one set of Lego and shows the relationship between the number of pieces in the set and the price in this example we are looking at the relationship between the weight of an orange and the weight of juice it yields each dot represents one orange and its position corresponds to the weight of the fruit and the weight of the juice you do not join up the dots in a sket plot you can see more about sket plots in our video about Scatter Plots time series plot a Time series plot is a special type of scatter plot this time series plot shows the number of visitors arriving in New Zealand each month from 1980 to 2015 the horizontal AIS is always in units of time equally spaced there is one observation for each time value in this case a month it makes sense to join up the dots in a Time series plot you can see that there is a repeating pattern you can see more about time series and time series graphs in our video understanding time series there are other types of graphs as well but we are not covering them in this video the choice of graph depends on the context and purpose of our investigation often more than one type of graph is appropriate good statistical packages will create appropriate graphs for your data this video was brought to you by statistics Learning Center visit our website for more resources to help 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