Assume that trees are subjected to different levels of carbo

Assume that trees are subjected to different levels of carbon dioxide atmosphere with 8% of the trees in a minimal growth condition at 360 parts per million (ppm), 12% at 470 ppm (slow growth), 46% at 570 ppm (moderate growth), and 34% at 630 ppm (rapid growth). What is the mean and standard deviation of the carbon dioxide atmosphere (in ppm) for these trees in ppm?

Assume that trees are subjected to different levels of carbon dioxide atmosphere with 8% of the trees in a minimal growth condition at 360 parts per million (ppm), 12% at 470 ppm (slow growth), 46% at 570 ppm (moderate growth), and 34% at 630 ppm (rapid growth). What is the mean and standard deviation of the carbon dioxide atmosphere (in ppm) for these trees in ppm?

Solution

The solution is presented in the form of a table

Mean value is obtd. as a weigthed average of all the four components

Mean = 561.5

Deviations = Deviation of CO2 levels from mean value

SD = sqrt of weighted average of the square of deviations

SD = 76.69

Ask if you have any doubts. Hope this helps.

	Percent	PPM	Product	Deviation	D^2	Per. * D^2
Minimal	0.08	360	28.8	-201.6	40642.56	3251.4048
Slow	0.12	470	56.4	-91.6	8390.56	1006.8672
Moderate	0.46	570	262.2	8.4	70.56	32.4576
Rapid	0.34	630	214.2	68.4	4678.56	1590.7104
	Total		561.6			5881.44
				Sdev		76.69054701