The average monthly rainfall in May for a specific county was recorded for a period of 10 years. Calculate the margin of error using half the range. (Use the exact value - don't round.)

Year Average monthly rainfall in May (in mm)
2004 28.8
2005 76.9
2006 48.8
2007 93.6
2008 31.0
2009 41.0
2010 98.0
2011 72.0
2012 109.0
2013 32.0