Question

news cameras take an overhead picture of a part of a crowd at an outdoor event. journalists then count the number of people in the picture and use the sample to estimate the total number of people in the crowd. this process is an example of random sampling. stratified sampling. systematic random sampling. cluster sampling.

Explanation:

In cluster sampling, the population is divided into clusters (here, the overhead picture of a part of the crowd can be considered a cluster), and we sample a cluster (the part in the picture) to estimate the whole population (the entire crowd). Random sampling would involve randomly selecting individuals, stratified sampling divides into groups with similar characteristics and samples from each, and systematic random sampling selects at regular intervals, which don't fit here. So this is cluster sampling.

Answer:

cluster sampling. (The option with "cluster sampling" text)