1. Handedness
Download the file handedness2008.txt and load it into R. This is the tabulated data of the in-class survey.

• Calculate the handedness ratio for each student (create a new vector) and draw a histogram. The ratio is given by (right-left)/(right+left).
• What is the median?
• What is the mean?
• What is the standard deviation?
• Is the distribution left or right skewed (by shape)?

2. CO₂ concentrations
Download the files co2last400000years.txt (Petit et al, Nature v.399 (6735), pp. 429-436. (1999)
Data originally downloaded from here ) and co2_mm_mlo.dat (http://www.cmdl.noaa.gov/projects/src/web/trends/co2_mm_mlo.dat, covering 1958-2006). Note that I have edited the files to remove the leading comments (which R would choke on if you don't warn it). If you download the files from the original source, make sure to use the skip argument of the read.table function.

• Load them both into R using read.table (careful, one of them has column headers and the other doesn't).
• First take the data since 1958. Create a new vector that contains both the year and month, for example 1980 04 becomes 1980+(4-1)/12 = 1980.25 (approximately, depending on whether the measurement was taken on the first of the month (as this assumes) or in the middle).
• Plot the CO₂ concentration vs. year. What trends do you observe?
• Now turn to the much longer scale data. The first column is the age of the ice core sample in years, the second column is the CO₂ concentration.
• Calculate a year column vector by subtracting the age from the current year (e.g. 2006-11719).
• Plot the CO₂ concentration vs. year, but extending the x-axis using the xlim parameter to include the year 2006, and adjusting the ylim parameter to go up to 400ppmv.
• Now use the points() function to add the data points from 1958-2006 in a different color. How do the CO2 levels in recent decades compare to the fluctuations over the last several hundred thousand years?

For both problems, submit a single PDF file that has the R commands you typed in, their output, your interpretation and the figures. The figures can be exported to a file or copied to the clipboard via the drop down menus.