Problem 2. (20 points) A river has the following record o the levels of floods that occurred each year between 2000 and 2010.
Year Flood level (m) 2000 3.7 2001 2.3 2002 5.1, 3.5 2003 5.2 2004 4.7, 6.1, 5.2 2005 3.4, 7.2, 1.5 2006 1.5, 3.6 2007 5.2, 1.4 2008 1.3, 4.5 2009 3.4 2010 4.4, 2.4
a) Draw the histogram of flood levels at 1-m interval. b) Draw the histogram of the annual maximum flood levels at 1-m interval. c) Based on the histogram, what is the return period for a maximum 7-m flood. d) Establish the 99% 2-sided confidence interval for the mean annual maximum flood. e) If the interval in d) to be reduced by 10% keeping the 99% confidence level, how many additional records have to be gathered.