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? Explain.

El Niño. Concern over the weather associated with El Niño has increased interest in the possibility that the climate on earth is getting warmer. The most common theory relates an increase in atmospheric levels of carbon dioxide (CO₂), a greenhouse gas, to increases in temperature. Here is part of a regression analysis of the mean annual CO₂ concentration in the atmosphere, measured in parts per million (ppm), at the top of Mauna Loa in Hawaii and the mean annual air temperature over both land and sea across the globe, in degrees Celsius. The scatterplots and residuals plots indicated that the data were appropriate for inference.

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? Explain.