Making and Interpreting Graphs3 Types of Graphs used in QRPie ChartsMost Common Pie Chart MistakesCreating a Pie ChartLabeling the ChartChart ThemesThe Result…XY GraphsNote: Don’t use the Line GraphCreating XY (Line) GraphsSlide 12Make Your Chart More ReadableSlide 14What’s the Story?Describing your graphBar Chart or Column ChartNote: Be CarefulCreating a Column ChartSlide 20Name Each Series in the legendSlide 22Add the other column of dataThe New ResultAdvantages of Multiple Bar ChartsDisadvantagesDescribing a Bar/Column ChartGuidelines for Creating an Effective GraphGuideline continued…Can the Graph Stand Alone?Faulty or Misleading GraphsY-axis Scale EffectsBad Chart ExamplesAnother Bad Example – Misleading GraphWeek 4LSP 120Joanna Deszcz3 Types of Graphs used in QRPie ChartsVery limited useCategory sets must make a wholeXY Graphs or Line GraphsUse with “a lot” of data pointsBar Charts or Column ChartsVery flexibleWork well with limited data Compares more than one seriesPie ChartsOnly used when have a quantitative variable associated with a list of categoriesBoth the categories and the quantities each add up to a wholeCategories must be disjoint – no overlappingMost Common Pie Chart MistakesUse on set of categories that don’t make a wholeUse on categories that overlapInclude total in chart dataLet’s try an exampleLeading Causes Of Death TabCreating a Pie ChartSelect labels and valuesChoose Pie chart typeChoose layoutMust include % value, title and labelsLayout 6 does it allAdd the source in a text boxLabeling the ChartTitle should be descriptiveConsider who, what, when and wherePercents should be formatted to 2 decimal placesFormat – Data Labels – Numbers – Percentage – 2 decimal placesSource – add in text boxInsert – Text Box – Draw text box on the chart and type in sourceIf not source give type “Unknown”Chart ThemesFound on Page Layout TabSlide mouse over built-in themes Chart will change to reflect each themeThe Result…Flow Theme applied to the chartXY GraphsUsed with a lot of dataX-axis categories are numeric, (often years)Choose xy graph option with connected data pointsNote: Don’t use the Line GraphExcel line graphs always treat the x-axis categorically instead of numericallyCauses endless array of mistakesUse XY (Scatter) graph instead to avoid errorsLet’s try one  Lake Michigan Levels TabCreating XY (Line) GraphsSelect category labels and valuesChoose Scatter chart optionScatter with straight lines and markers type2nd row, 2nd columnChoose design layout 1 from Design tabLabeling the ChartTitle should be descriptiveConsider who, what, when and whereRemove the legend from the chartNot needed when there is only one seriesSource – add in text boxInsert – Text Box – Draw text box on the chart and type in sourceIf not source give type “Unknown”Apply a theme if you wishMake Your Chart More ReadableXY Graphs often only take up a small range of valuesIf all data points located in a central area on the graphAdjust y-axis so values start at or just below the lowest data point value•Right-click on y-axis•Choose Format axis•Adjust Minimum valueThe Result…Solstice Theme applied to this chartWhat’s the Story?XY (Line) Graphs usually tell a story about the dataAnalysis should carefully describe what the graph is sayingStart the “story” from the left and move to the rightBe sure to include the high point and the low point as well as anything that is interesting or unexpectedWrite a well-written paragraph telling the “story”Describing your graphIn a paragraph, point out what you want the reader to know about the graphExamples:“In the Annual Averages of Lake Michigan/Lake Huron Water Levels chart we find that between 1988 and 1997 water levels in the lakes increased overall. The high point of the lake levels occurred in 1997 when the level was 176.98 meters. However, lake levels took a sharp decline in the following 2 years and reached their low point in 2003 when the level was only 175.89 meters. Since 2003 lake levels have increased slightly but appear to be declining once again.”Bar Chart or Column ChartVery flexibleUsed when a quantitative variable is associated with the a categorical variableWork well with limited dataCan compare more than one seriesNote: Be CarefulIf you do use a bar chart and have years along the x-axisBe sure the years are in equal intervals. Otherwise, you can be guilty of creating a misleading graphLet’s try one Home Heating TabCreating a Column ChartSelect the data including category labels and valuesChoose Column Chart2-D Clustered column optionAdd Titles and axis labelsLayout 9 works wellLabeling the ChartTitle should be descriptiveConsider who, what, when and whereBoth the x-axis and y-axis should be labeledSource – add in text boxInsert – Text Box – Draw text box on the chart and type in sourceIf not source give type “Unknown”Apply a theme if you wishName Each Series in the legendTo change namesClick on chart to activateClick on Design TabUnder Data Group – choose Select DataData Series labels appear on leftHighlight label and click edit button Type new series name in Edit Series Dialog boxThe Result…Aspect Theme applied to chartSource: US Dept of EnergyAdd the other column of dataReselect the data to include all 3 columnsThe New ResultSource: US Dept. of EnergyAdvantages of Multiple Bar ChartsSuccinctnessCan make comparisons within categories and across categoriesBest used in printed worksCan be carefully studiedDisadvantages Can present too much information to view as part of presentationHard to make a single clear point with bar chartsPresenters don’t leave them up long enough to absorb info fullyDescribing a Bar/Column ChartUsually include high and low values in graph descriptionNot always effective/appropriate with bar/column chartsInclude top 2 or 3 values insteadLow value may be insignificantOften describes “Other” categoryNot significant in the “story”Guidelines for Creating an Effective Graph1. What is the purpose of making a graph from this data?2. What type of graph should you make? Pie, bar, x-y scatter (line) 3. Decide