The Basic Practice of Statistics SEVENTH EDITION DAVID S. MOORE, Purdue University WILLIAM I. NOTZ, The Ohio State University, MICHAEL A. FLIGNER, University of California at Santa Cruz Chapter-21 Comparing Two Means Copyright © 2015 by W. H. Freeman and Company

Chapter Opener, The Basic Practice of Statistics, © 2015 W. H Chapter Opener, The Basic Practice of Statistics, © 2015 W. H. Freeman, © Javier Larrea/age fotostock

Table 21.1, The Basic Practice of Statistics, © 2015 W. H. Freeman

Figure 21.1, The Basic Practice of Statistics, © 2015 W. H. Freeman

Figure 21.2, The Basic Practice of Statistics, © 2015 W. H. Freeman

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Figure 21.3, The Basic Practice of Statistics, © 2015 W. H. Freeman

Figure 21.4, The Basic Practice of Statistics, © 2015 W. H. Freeman

Figure 21.5, The Basic Practice of Statistics, © 2015 W. H. Freeman

Table 21.2, The Basic Practice of Statistics, © 2015 W. H. Freeman

Figure 21.6, The Basic Practice of Statistics, © 2015 W. H. Freeman

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Table 21.3, The Basic Practice of Statistics, © 2015 W. H. Freeman

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Table 21.4, The Basic Practice of Statistics, © 2015 W. H. Freeman