LSP 120The Graphs We Will UseBut…Pie ChartsSlide 5Pie GraphsSlide 7Slide 8Bar / Column ChartsSlide 10XY Scatter Graphs / Line GraphsSlide 12Slide 13Describing GraphsFaulty GraphsCreating GraphsPie graphsBar / column graphsLine graphsXY scatter graphsEach graph works best in a particular situationYou need to decide which is bestSome will work, some won’t work, there is usually one really good choice, there are often some really bad choicesLet’s look at each graph choiceYou must have all the data in order to use a pie chartFor example, if you are graphing choices of cookies, and the only data you have is:◦Oreo 235 million units sold◦Chips Ahoy 211 million units sold◦Lorna Doone 145 million units sold•Don’t make a pie chart like this:•What is wrong with this graph?Secondly, make sure the data does not overlapConsider the following data:◦DSL users 26%◦Cable modem users 19%◦Dial up users 32%◦None 23%◦Total 100%Note: there is no title on this graphFinally, don’t make a pie with too many slicesLook at EnergyConsumption.xlsBar / column charts are good when you want to show “amounts” or “levels” of somethingFor example, four different cities each have a value for the number of traffic accidents:◦Chicago 3211 accidents◦Detroit 2210 accidents◦St. Louis 1349 accidents◦Fort Wayne 832 accidentsLook at HomeHeating.xlsThese graphs are best at showing how one type of data input changes one outputFor example, how as time changes, the sales have gone upOr, as a person’s height increases, so does their weightOr, as you drink more drinks, the more drunk you will getBe careful: A line graph will not treat the first column as X-axis labels; it will treat it as a series of dataLook at Headstart Per Child.xlsYou should know how to “describe” a graph◦Is the graph/data increasing? Decreasing? Flat? Cyclic or periodic?◦What is the global or absolute maximum? Minimum?◦What is a local or relative maximum? Minimum?Let’s look at some “faulty”