23. The time series graph is given below. Note that the given years are not evenly spaced. YearTransistors (1000's)200520001995199019851980197519704000003000002000001000000TRANSISTORS PER SQUARE INCH24. The time series graph is given below. The graph does not appear to show linear growth (constant slope) over the entire time period, but it does appear that there was linear growth during certain periods (e.g., since 1999). Yearsubscribers (1000's)200520032001199919971995199319911989198719852000001750001500001250001000007500050000250000US CELL PHONE SUBSCRIPTIONS

36 CHAPTER 2 Summarizing and Graphing Data rate per 1000121086420MARRIAGE AND DIVORCE RATESM DM DM DM DM D M DM DM DM DM DM D1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000M = marriage rateD = divorce rate26. The multiple bar graph is given below. The females consistently outnumber the males, and the numbers of both genders are gradually increasing over time. students (1000's)120001000080006000400020000GENDERS OF STUDENTSM FM FM FM FM FM FM F2004 2005 2006 2007 2008 2009 2010M = maleF = femaleyear27. The back-to-back stemplot is given below. The pulse rates for men appear to be lower than the pulse rates of women. PULSE RATES Women | | Men .| 5 | 666666 888884444000 | 6 | 00000004444444888 66666622222222 | 7 | 22222266 88888000000 | 8 | 44448888 6 | 9 | 6 4 | 10 | | 11 | 4 | 12 |

Statistical Graphics SECTION 2-4 37 28. a. The next two rows of the expanded stemplot come from the original 70’s row as follows. 7 | 22222222 7 | 666666 b. The completed condensed stemplot is as follows. FEMALE PULSE RATES stem | leaves .6−7 | 000444488888*22222222666666 8−9 | 00000088888*6 10−11 | 4* 12−13 | 4* 2-5 Critical Thinking: Bad Graphs 1. The illustration uses two-dimensional objects (dollar bills) to represent a one-dimensional variable (purchasing power). If the illustration uses a dollar bill with ½ the original length and ½ the original width to represent ½ the original purchasing power, then the illustration is misleading (because ½ the length and ½ the width translates into ¼ the area and gives the visual impression of 25% instead of 50%). But if the illustration uses a dollar bill with ½ the area (i.e, with .707 of the original length and .707 of the original width) to represent ½ the original purchasing power, then the illustration conveys the proper visual impression. 2. No. Since the data comes from a voluntary response sample it may not be representative of the population. Since the sample may not be representative, even sound graphing techniques will not necessarily provide accurate understanding of the population.