Chapter 3 Slides

# Chapter 3 Slides - Chapter 3 Experimental Error Measure of...

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1 Chapter 3 Experimental Error Dr. Elizabeth Binamira-Soriaga Department of Chemistry Measure of Central Tendency: The Mean X i = ith measurement n = # of measurements The mean, X, or the average, is the sum of the measured values divided by the number of measured values X = X n i = 1 n " n X = 21.821 7 = 3.117 g Measure of Central Tendency: The Median The median, X med , is the middle value when the data are ordered from the smallest to the largest 3.056 3.080 3.094 3.107 3.112 3.174 3.198 For even #: X med = average of n/2 and (n/2) + 1 measurements The median, X med , is the value in an ordered set for which half of the data is larger in value and half is smaller in value 3.056 3.080 3.094 3.107 3.112 3.174 X med = 3.101 Measure of Spread: Standard Deviation The standard deviation, s, measures how closely the measured values are clustered about the mean s = X i " X ( ) 2 i = 1 n # n " 1 s = 0.01556 7 " 1 = 0.051 Variance: s 2 Relative standard deviation, s

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## This note was uploaded on 02/15/2010 for the course CHEM 316 taught by Professor Soriaga during the Fall '08 term at Texas A&M.

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Chapter 3 Slides - Chapter 3 Experimental Error Measure of...

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