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Chapter 1 1.1(a) The sum of the weights is 231.8 million tons. (b) Bar graphs are shown below. MaterialPercent of totalOtherYard trimmingsWoodRubber, leather, textilesPlasticsPaper. PaperboardMetalsGlassFood scraps403020100MaterialPercent of totalOtherWoodGlassRubber,leather,textilesMetalsPlasticsFood scrapsYard trimmingsPaper. Paperboard403020100(c) A pie chart is shown below. CategoryPlasticsRubber, leather, textilesWoodYard trimmingsotherFood scrapsGlassMetalsPaper. Paperboard1.2 In order to know what percent of owners of portable MP3 players are 18 to 24 years old, we would need to know two things: The number of people who own MP3 players, and the number of those owners in that age group. The Arbitron data tells us neither of those things. 1.3 (a) The stemplot does a better job, the dots in the dotplot are so spread out, it is difficult to identify the shape of the distribution. (b) The numbers in the left column show cumulative counts of observations from the bottom up and the top down. For example, the 5 in the third row indicates that 5 observations are at or below 1.09. The (3) in the far left column is Minitab’s way of marking the location of the “middle value.” Instead of providing a cumulative count, Minitab provides the number of leaves (observations) in the row that contains the center of the distribution. The row with the parentheses also indicates where the cumulative counts switch from the bottom up to the top down. For example, the 7 in the 10throw indicates that 7 observations are at or above 1.72. (c) The final concentration, as a multiple of its initial concentration should be close to 1. This sample is shown as the second dot from the left on the dotplot and in the second row of the stemplot. The sample has a final concentration of 0.99. 1.4 (a) Liberty University is represented with a stem of 1 and a leaf of 3. Virginia State University is represented with a stem of 1 and a leaf of 1. The colleges represented with a stem of 2 and a leaf of 1 are: Hollins; Randolph-Macon Women’s; Sweet Briar; William and Mary. (b) These 23 twos represent the 23 community colleges. The stem of 0 represents all colleges and universities with tuition and fees below $10,000. 11
1.5 The distribution is approximately symmetric with a center at 35. The smallest DRP score is 14 and the largest DRP score is 52, so the scores have a range of 38. There are no gaps or outliers.Degree of Reading Power484236302418Stem-and-leaf of DRP N = 44 Leaf Unit = 1.0 2 1 44 6 1 5899 7 2 2 15 2 55667789 20 3 13344 (6) 3 555589 18 4 00112334 10 4 5667789 3 5 122 1.6 (a) and (b) The stemplots are shown below. The stemplot with the split stems shows the skewness, gaps, and outliers more clearly. (c) The distribution of the amount of money spent by shoppers at this supermarket is skewed to the right, with a minimum of $3 and a maximum of $93. There are a few gaps (from $62 to $69 and $71 to $82) and some outliers on the high end ($86 and $93).