Comparing means of distributionsMeans and medians of different distributionsImpact on median & mean: removing an outlierImpact on median & mean: increasing an outlierMean as the balancing pointMissing value given the meanMedian & range puzzlers
Measures of spread: range, variance & standard deviationVariance of a populationPopulation standard deviationThe idea of spread and standard deviationCalculating standard deviation step by stepMean and standard deviation versus median and IQRConcept check: Standard deviationStatistics: Alternate variance formulas
Why we divide by n - 1 in variance Simulation showing bias in sample varianceSimulation providing evidence that (n-1) gives us unbiased estimateUnbiased estimate of population varianceReview and intuition why we divide by n-1 for the unbiased sample variance
Worked example: Creating a box plot (odd number of data points)Worked example: Creating a box plot (even number of data points)Constructing a box plotReading box plotsInterpreting box plotsBox plot reviewJudging outliers in a datasetIdentifying outliers with the 1.5xIQR rule
This unit covers common measures of center like mean and median. We'll also learn to measure spread or variability with standard deviation and interquartile range, and use these ideas to determine what data can be considered an outlier.