# 4) - Calculating Percentiles: 1. Arrange data in ascending...

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Statistics 5e 4/4/08 Percentiles: measures of relative positions Quartiles: divides the data into 4 equal parts (4 th s) Percentiles divide data into 100 equal parts – the pth percentile is a value such that at least p% of the data points are less that or equal to this value and (100-p)% of the data points are greater than or equal to this value. The first quartile, Q 1 , is the 25 th percentile The second quartile, Q 2 , is the median The third quartile, Q 3 , has 75% of the data to its left.
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Unformatted text preview: Calculating Percentiles: 1. Arrange data in ascending order 2. Compute index “i” i= (P/100)n n=sample 3. If “i” is not an integer, then round up (pth percentile). If “i” is an integer, then pth percentile is the average of “i” and i+1 Measures of Variability Range : Largest Value – Smallest Value Interquartile Range (IQR): IQR = Q 3-Q 1 Standard Deviation : (SD) measures how far a number on a list is away from the list average...
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## This note was uploaded on 04/08/2008 for the course PSTAT 5E taught by Professor Eduardomontoya during the Spring '08 term at UCSB.

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