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## Chapter 5 Describing Distributions Numerically

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**Chapter 5Describing Distributions Numerically***Mean, Median *Range, Standard Deviation, IQR *Box-and-Whisker Plots (Box Plots) *5 number summary**Remember!?!**• Mean: add up all the data values then divide by the number of values • Median: the middle number in an arranged set of data (if there is no middle number find the mean between the two middle numbers) • Range: max value – min value**Patriots Salaries 13 - 14**• Find the mean, median, and range for the data**When to use what?**• When your data is skewed • center: median • range: Interquartile Range (IQR) • When your data is symmetric • center: mean • range: standard deviation (SD) **Always check the distribution of the data before deciding which measure of center and spread to use****5 Number Summary**• Minimum • Lower Quartile (Q1) [median of lower 50% of the data] • Median • Upper Quartile (Q3) [median of the upper 50% of the data] • Maximum • Calc: • enter data into the list • STAT ; CALC ; 1: 1 – VAR Stats**How to Determine an Outlier**• If a data value is more than 1.5 times the IQR away from the upper or lower quartile it is an outlier • Q1 – 1.5IQR • Q3 + 1.3IQR**Box-and-Whisker Plots(Box Plots)**• A way to display the 5 number summary