(a) Define each of the following terms used in the measurement of plant sizes: (
ID: 3510205 • Letter: #
Question
(a) Define each of the following terms used in the measurement of plant sizes: (i) Mean, (ii) Variance, (iii) Standard deviation
(b) The following data was obtained from a study of an ecosystem in which 10 different species were randomly identified and their heights measured. As a Research Assistant for Plant Ecology Laboratory, determine:
(i) Mean height of all species combined
(ii) Variance as a measure of variability in plant height
(iii) Standard deviation SPECIES HEIGHT(cm)
1. Beech (Fagus spp.) 300
2. Hackberry (Celtis occidentalis) 90
3. Southern red oak (Quercus faclcata) 80
4. Dogwood (Comus florid) 600
5. Longleaf Pine (Pinus palustris) 2,450
6. Magnolia (Magnolia sp.) 1,250
7. Red Maple (Hacer rurua) 710
8. Shortleaf Pine (Pinus echinata) 1,350
9. Sweetgum (Liquidamba styracilua) 1,210
10. Wax Myrtle 1,150
11. Cabbage palmetto (Sabal palmetto) 60
12. Live oak (Quercus rubra) 2,055
13. Water oak (Q. nigra) 1,925
14. Scarlet oak (Q. coccinea) 1,075
15. Bald cypress (Taxodium distichum) 996
16. Black hickory (Carya sp.) 878
17. Black oak (Q. macrocarpa) 1,225
18. Wild Blackberry (Prunus serotina) 1,027
19. Eastern Cottonwood (Populus deltoides) 800
20. Virginia pine (Pinus virginiana) 1,330 c)
Given the data as indicated above,
(i) Is this a predominantly terrestrial or aquatic ecosystem? Why?
(ii) Would you consider this a mixed hardwood/pine ecosysyetm?
(iii) Which plant species form the overstory of this ecosystem?
(iv) Is this a stable community?
Explanation / Answer
a. (i) Mean can be defined as the average of the numbers; for plant sizes it means the average plant size of all the total plants present. Mean is the calculated central value of a range of numbers.
(ii) Variance is the measure of variation and is the sum of square of deviations divided by the total number of observations.
(iii) Standard deviation is the square root of the sum of the squares of the deviations from arithmetic mean divided by total number of observations. It is the square root of variance.
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