Section 2.2- In-class project Name: David Burgos Numbers of Children of Those Who Signed the Declaration of Independence 12 18 7 4 10 2 7 13 8 9 11 9 10 3 13 3 15 7 12 4 1 WHITE 8 16 3 3 7 5 7 8 13 5 6 3 3 2 5 21753 23632 7 5968 5 Step 1: find the number of classes. 2 k> n (k = classes; n = number of ages) 2k 50 Step 2: find the class width. Range of scores: 18-1 = 17, 17/6 6.8333 (round up) Step 3: establish your Lower Class Limits. Start with lowest age, add to it until you have. lower limits; your Upper Class Limits will always be one less than the following Lower Class Limit Class Tally Freq, f Relative Freq. Cumulative Freq Midpoint 50 50 100% Because consecutive bars must touch, we can't use the class limits (in the chart above, 14-20 is the first set of class limits); instead, we must use Class Boundaries - numbers that separate the classes without forming gaps. To do this, we subtract 0.5 from each lower limit to find the lower boundaries and add 0.5 to each upper limit to find the upper boundaries. 0.5 3.5, 3.5-6.5, 6.5-9.5, 9.5 - 12.5, 12.5-15.5, and 15.5-18.5. Because the data entries are integers (whole numbers), they will always fall between the class boundaries. Histogram using class boundaries Histogram using midpoints of classes The following table is a portion of a data set from www.worldbank.org. Use the table to construct a time series graph for CO2 emissions for the United States. CO2 Emissions Ukraine United Kingdom United States 2003 352,259 540,640 5,681,664 2004 343,121 540,409 5,790,761 2005 339,029 541,990 5,826,394 2006 327,797 542,045 5,737,615 2007 328,357 528,631 5,828,697 2008 323,657 522,247 5,656,839 2009 272,176 474,579 5,299,563