chapter2-study-guide

# chapter2-study-guide - AP Statistics Study Guide Chapter 2...

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AP Statistics Study Guide Chapter 2 Page 1 Mr. Martin September 27, 2010 Measuring Relative Standing Standardized Values and z-scores Percentiles Rank the data lowest to highest. Counting up from the lowest value to the select data point we discover the percentile that is represented by the data. For Example: Suppose that you received a 78 on a 90 point quiz. You are ranked 30 th out of the 50 individual who took the test. Your score is: 30 .6 100 60% 50 = •= or in the 60 th percentile. 40% of the students ranked higher than you. Another definition is that “For any particular number p between 0 and 100, the p th percentile is a value such the p percent of the observations in the data set fall at or below that value”. Introduction to Statistics & Data Analysis Peck, Olsen, and Devore Thomson (2008) ISBN 10: 0-495-11873-7

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AP Statistics Study Guide Chapter 2 Page 2 Mr. Martin September 27, 2010 Density Curves 1. Always plot your data: make a graph, usually a histogram or stemplot. 2. Look for the overall pattern (shape, center, spread) and for striking deviations such as outliers . 3. Calculate a numerical summary to briefly describe center (median or mean), spread (range, IQR, standard deviation) 4. Sometimes the overall patter of a large number of observations is so regular that we can describe it by a smooth curve. Doing so can help us describe the location of individual observations with a distribution.
AP Statistics Study Guide Chapter 2 Page 3 Mr. Martin September 27, 2010 Normal Curve Bell shaped density curve with several key properties: A density curve that is: Symmetric Single peaked Bell shaped Describes a Normal distributions Empirical Rule (68-95-97.9) Remember these are percentages – percentages are a proportion!

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AP Statistics Study Guide
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## This note was uploaded on 12/09/2011 for the course STAT 101 taught by Professor O during the Fall '08 term at Lake Land.

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chapter2-study-guide - AP Statistics Study Guide Chapter 2...

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