Question

find the technique for gathering data in the study below. the colorado division of wildlife imposed special fishing regulations on the deckers section of the south platte river. all trout under 15 inches had to be released. a study of trout before and after the regulations went into effect showed that the average length of trout increased by 4.2 inches after the new regulations.

observational study
experiment
census
sampling
none of these choices

Explanation:

In an observational study, researchers observe and measure characteristics of a population without trying to manipulate or intervene. Here, the study just observes the trout lengths before and after regulations without any experimental manipulation. An experiment would involve deliberately changing something to see the effect. A census is a count of an entire population, and sampling is about selecting a subset of the population. Since the study is just observing the natural - occurring situation of trout lengths before and after regulations, it is an observational study.

Answer:

observational study