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Dataquest http://data1.cde.ca.gov/dataquest/. Examining Distributions: Skewed. Symmetric (approx. Normal) Distributions. DON’T FORGET YOUR SOCS!. To describe a distribution, address the following: S HAPE O UTLIERS (definition…) C ENTER S PREAD. A note on outliers.
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DON’T FORGET YOUR SOCS! To describe a distribution, address the following: • SHAPE • OUTLIERS (definition…) • CENTER • SPREAD
A note on outliers • Carefully examine an outlier before deciding whether or not to include it in your calculations. Ask yourself: is this data representative? • Heavily affects mean/standard deviation • Does not affect median/5# summary
What to use and when If describing a skewed distribution: Spread: 5 # Summary (Min, Q1, Med, Q3, Max) Center: Median If describing a symmetric distribution: Spread: Standard Deviation Center: Mean
Example Data Set: 1 2 4 8 20 • Find 5# Summary • Find Standard deviation • Outliers?
One more correlation example…….. # of Ministers in Boston Vs. Cases of Rum!