lecture+4

# lecture+4 - summary of both center and spread The...

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January 16, 2008 [ LECTURE 4 ] 1 What you need to remember from today’s lecture I. Measure of spread: quartiles and standard deviation Quartiles are three numbers that describe the trend, or statistically, the spread of the data. The calculation of the quartiles is important and essential. Note that the second quartile is actually the mean. Instructions about how to find the quartiles: The standard deviation is used to describe the variation around the mean. Steps for calculating the standard deviation:

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January 16, 2008 [ LECTURE 4 ] 2 II. The five-number summary and boxplots There are five numbers related to a distribution that can give a brief and straightforward
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Unformatted text preview: summary of both center and spread. The five-number summary of a distribution consists of the smallest observation, the first quartile, the median, the third quartile and the largest observation, written in order from smallest to largest. The five-number summary is summarized as: Minimum Q ଵ M Q ଷ Maximum Moreover, the five-number summary of a distribution leads to a new graph, the boxplot . January 16, 2008 [ LECTURE 4 ] 3 A boxplot is a graph of the five-number summary: A central box spans the quartiles Q ଵ and Q ଷ . A line in the box marks the median M. Lines extended from the box out to the smallest and largest observations....
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lecture+4 - summary of both center and spread The...

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