GCSE›Edexcel GCSE Maths›Mind mapsStatistical RepresentationsEdexcel GCSE Maths: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsBasic chartsBar, pie and pictogram show categorical dataPie angle =ftotal×360°= \frac{f}{\text{total}} \times 360°=totalf×360°Pictogram must have a keyBar charts: equal width with gapsHistogramsContinuous data: bars touchEqual widths: height = frequencyUnequal widths: use frequency densityfd=frequencyclass width\text{fd} = \frac{\text{frequency}}{\text{class width}}fd=class widthfrequencyArea of bar = frequencyCumulative frequencyRunning total of frequenciesPlot at upper class boundaryJoin with a smooth curveMedian at 12\frac{1}{2}21, LQ at 14\frac{1}{4}41, UQ at 34\frac{3}{4}43IQR=UQ−LQ\text{IQR} = \text{UQ} - \text{LQ}IQR=UQ−LQStatistical chartsdrawing and reading datafdCFIQRBox plotsFive values: min, Q1, median, Q3, maxCompare medians for typical valueCompare IQR or range for spreadMedian off-centre in box shows skewScatter graphsPositive: both variables rise togetherNegative: one rises, the other fallsLine of best fit balances pointsInterpolation is inside the data rangeExtrapolation is beyond it, so less reliableCorrelation is not causationTime seriesTrend = overall directionSeasonality = regular repeating patternMoving average smooths fluctuationsPlot moving average at the centre of its period