. One in one hundred. Thats the ratio of individuals in the U.S. population with

Chapter 11, Problem 57

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. One in one hundred. Thats the ratio of individuals in the U.S. population with autistic disorder, better known as autism. The disorder involves severe deficits in language, social bonding, and imagination, and is often accompanied by mental retardation. The bar graph shows the number of autism cases diagnosed in the United States from 2001 through 2008. Autism Cases Diagnosed in the United States Year 2001 100 2002 120 2003 145 2004 170 2005 200 2006 220 2007 260 2008 300 50 100 150 200 250 300 350 Number of Cases Diagnosed (thousands) Source: Lilienfeld et al., Psychology, Second Edition, Pearson, 2011. Let an represent the number of autism cases diagnosed in the United States, in thousands, n years after 2000. a. Use the numbers given in the graph to find and interpret a 8 i=1 ai . b. The finite sequence whose general term is an = 28n + 63, where n = 1, 2, 3,c, 8, models the number of autism cases diagnosed in the United States, in thousands, n years after 2000. Use this model to find a 8 i=1 ai. Does this underestimate or overestimate the actual sum in part (a)? By how much?