Paper 2 · CBD land-use survey methodology
A study area is sampled using two different point-sampling techniques. In Technique A, points are selected at random locations across the whole area, giving every location an equal chance of selection. In Technique B, the area is first divided into two contrasting sub-zones using a boundary line, and points are then sampled unevenly within each sub-zone. What is Technique B called?
ACluster sampling, in which whole neighbouring groups of points are selected together as a single sampling unit
BRandom sampling, in which every point in the area has an equal, independent chance of being selected
CStratified sampling, in which the area is divided into sub-zones, and points are then sampled within each one
DSystematic sampling, in which points are selected at fixed, evenly-spaced intervals across the whole area
Explanation: Technique B divides the area into contrasting sub-zones before sampling, which is the defining feature of stratified sampling: it guarantees that each sub-zone is represented in the results rather than leaving that to chance. Technique A, where points are picked with no fixed pattern or sub-division, is random sampling. Systematic sampling instead uses a fixed spacing between points, and cluster sampling selects whole neighbouring groups together, neither of which matches the sub-zone division described here.
Derived from ZIMSEC Geography Paper 2, November 2004, Q2
