ENVS178 Lecture Notes - Lecture 4: Unimodality, Quartile, Interquartile Range
15 Jun 2015
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Document Summary
Range: max-min (total spread) (very sensitive to outliers) Percentiles - the pth percentile of a distribution is the value such that p percent of the values fall below this value. Quartiles - lower quartile 25%smaller 75%larger, median, and upper quartile. Five number summary: min, lq, median, uq, max. Use the median to divide the ordered array into two parts. Five number summary can be presented graphically as a boxplot. Difference between the first and third quartile. Average of the squared deviations from the mean. Can"t compare standard deviation of different distributions. Calculated to neutralize the effects of both inconsistent untis of measurement and differences in means. Unitless and is a measure of relative variability. Statistic that summarizes the degree of variability about the mean. The standard deviation used as a unit of measurement. useful for indicating where a particular observation sits in the distribution. The point subtract the mean, all over the standard of deviation.
