Q103 · Practice questionComplex familiar1 mark
QUESTION 103
Two samples each contain three equally abundant species. Sample P contains 5 individuals of each species; sample Q contains 30 of each. Use . Which statement is correct?
(A)
P has a slightly higher finite-sample SDI although both samples have the same richness and evenness.
(B)
Q is more even because it contains more individuals.
(C)
P has higher species richness because its SDI is higher.
(D)
The two SDIs must be identical because all three species are present.
WORKED SOLUTION
1 markAnswer A
Answer
A
Working
P gives 1 − 3(5)(4)/(15×14) = 0.714; Q gives 1 − 3(30)(29)/(90×89) = 0.674. Both have richness 3 and equal relative abundances. The finite-sample index can differ with sample size even when those proportions match.
Marking criteria
- Select A. [1 mark]
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
View the QCAA syllabus