Assume that trees are subjected to different levels of carbon dioxide atmosphere with 8% of the trees in a minimal growth condition at 350 parts per million (ppm), 11% at 440 ppm (slow growth), 48% at 560 ppm (moderate growth), and 33% at 640 ppm (rapid growth). what is the mean and standard deviation of the carbon dioxide atmosphere (in ppm) for these trees? the mean is ppm. [round your answer to one decimal place (e. g. 98.7).] the standard deviation is ppm. [round your answer to two decimal places (e. g. 98.76).]