IGCSE›Edexcel IGCSE Maths›Mind mapsStatistics ToolkitEdexcel IGCSE Maths: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsFour measuresMean = sum of values ÷ number of valuesMedian = middle value once orderedMode = most frequent valueRange = largest − smallestnnn even → median is mean of two middle valuesFrequency tablesAdd a column for x×fx \times fx×fxˉ=∑fx∑f\bar{x} = \frac{\sum fx}{\sum f}xˉ=∑f∑fxMode is the xxx with the highest frequencyUse cumulative frequency to find median positionGrouped dataUse the midpoint of each classMidpoint = (lower + upper) ÷ 2Result is an estimated meanAssumes every value sits at the midpointStatisticsaverages and spreadxˉ\bar{x}xˉ∑fx\sum fx∑fxClassesModal class = highest frequency intervalMedian class contains the middle valueMedian position is n2\frac{n}{2}2nGive the whole interval, never one numberComparingComment on an averageComment on the spreadBoth written in contextSmaller range → more consistentExam tipsOrder the data before finding the medianRange is one number, not "4 to 9"Divide ∑fx\sum fx∑fx by ∑f\sum f∑f, not the rowsWrite "estimated mean" for grouped data