For each of the following studies, identify the source(s) of sampling bias and d

Question

For each of the following studies, identify the source(s) of sampling bias and describe

(i) how it might affect the studyconclusions?

(ii) how you might alter the sampling method to avoid the bias?

1. To study the size (radius) distribution of scrub oaks (shrubby oak trees), 20 oak trees were selected by using random latitude / longitude coordinates. If the random coordinate fell within the canopy of a tree, the tree was selected; if not, another random location was generated.

(Note we are assuming 20 oak trees are scrub oaks!)

Explanation / Answer

ANS=

Larger trees tend to have larger canopies and they also tend to partly occlude the canopiesof the smaller trees, and so the results will be biased towards the larger trees. One may dividethe land into (reasonably big) rectangular patches according to latitude and longitude and thenselect a few of the patches randomly. Then measurements of all the trees falling in that patchcan be taken. This is an example of a cluster sampling scheme where the rectangular patchescorrespond to the clusters.

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.