GCSE›AQA GCSE Maths›Mind mapsAnalysing DataAQA GCSE Maths: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsAveragesMean: total ÷ number of valuesMedian: middle value in orderMode or modal class: most commonPopulation described by summary measuresSpreadRange = largest − smallestIQR =Q3−Q1= Q_3 - Q_1=Q3−Q1 (Higher)IQR is less affected by outliersOutlier: unusually far from the restHistogramsFor grouped data with unequal class widthsfrequency density=frequencyclass width\text{frequency density} = \frac{\text{frequency}}{\text{class width}}frequency density=class widthfrequencyBar area shows frequencyFrequency = density × class widthAnalysing dataaverages and spreadQ1Q3IQRCumulative, box plotsPlot running total against upper boundaryRead median and quartiles from the curveBox plot: min, Q1Q_1Q1, median, Q3Q_3Q3, maxCompare median and IQR of two setsScatter graphsPositive: both increaseNegative: one increases, the other fallsStrong or weak: how close to a lineInterpolate (safer) vs extrapolateExam tipsOutliers: use median and IQRDo not read frequency from height if widths differCorrelation is not causation