Data collected from around the globe (including the sea ice data of Exercise 23) show that the earth is getting warmer. The generally accepted explanation relates climate change to an increase in atmospheric levels of carbon dioxide (CO₂) because CO₂ is a greenhouse gas that traps the heat of the sun. A standard source of the mean annual CO₂ concentration in the atmosphere (parts per million) is measurements taken at the top of Mauna Loa in Hawaii (away from anylocal contaminants) and available at ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_annmean_mlo.txt. Global temperature anomaly is the difference in mean globaltemperature relative to a base period of 1981 to 2010 in °C. It isavailable at www.ncdc.noaa.gov/cag/data-info/global. Here are a scatterplot and regression for the years from 1959 to 2016:

a) Write the equation of the regression line.
b) Is there evidence of an association between CO₂ level and global temperature?
c) Do you think predictions made by this regression will be very accurate?
d) Does this regression prove that increasing CO₂ levels are causing global warming?

Temp 0.75 0.50 0.25 0.00 325 www. 350 CO 375 400