Forests are complex, evolving ecosystems. For instance, pioneer tree species can
ID: 3257248 • Letter: F
Question
Forests are complex, evolving ecosystems. For instance, pioneer tree species can be displaced by successional species better adapted to the changing environment.
Ecologists mapped a large Canadian forest plot dominated by Douglas fir with an understory of western hemlock and western red cedar.
Sapling trees (young trees shorter than 1.3 meter) are indicative of the future of a forest.
The 246 sapling trees recorded in this sample forest plot were of the following types:
Data Set
Is there an equal proportion of RC, DF, and WH among sapling trees in this forest?
What does your analysis suggest about this forest’s successional stage? Follow the four-step process in reaching your answer.
Step 1:
STATE: Are the three trees species equally represented among sapling trees in this forest?
FORMULATE: State the null and alternative hypotheses that should be tested to answer the question.
Step 3:
SOLVE (continued): Give the chi-square statistic and use Table D to find the P-value.
Step 4:
What does your analysis suggest about this forest's successional stage?
Forests are complex, evolving ecosystems. For instance, pioneer tree species can be displaced by successional species better adapted to the changing environment.
Ecologists mapped a large Canadian forest plot dominated by Douglas fir with an understory of western hemlock and western red cedar.
Sapling trees (young trees shorter than 1.3 meter) are indicative of the future of a forest.
The 246 sapling trees recorded in this sample forest plot were of the following types:
Data Set
Is there an equal proportion of RC, DF, and WH among sapling trees in this forest?
What does your analysis suggest about this forest’s successional stage? Follow the four-step process in reaching your answer.
Step 1:
STATE: Are the three trees species equally represented among sapling trees in this forest?
FORMULATE: State the null and alternative hypotheses that should be tested to answer the question.
Step 3:
SOLVE (continued): Give the chi-square statistic and use Table D to find the P-value.
Step 4:
What does your analysis suggest about this forest's successional stage?
Explanation / Answer
(1) H 0: pRC = pDF = pWH = 1/3 vs. Ha: at least one pi is not 1/3.
(2)
(3) 2 = 164, P < 0.0005.
(4) There is strong evidence that the three tree species are not equally represented among sapling in this forest.
RC 164 82 82 DF 0 82 82 WH 82 82 0 2 = 164