What is an observational study?

A) An observational study is a list of all individuals in a population along with a certain characteristics of each individual.

B) An observational study is whn a researcher assigns individuals to a certain group, intentionally changing the value of an explanatory variable, and then recording the value of the responses variable for each.

C) An observational study measures the value of the response variable without attempting the influence the value of either the response or explanatory variables

Option C) is the correct answer.

Step-by-step explanation:

Observational study:

It is the process of drawing inferences or observation from a sample about the population. In an observational study, the independent variable is not under control. Thus, we cannot change the independent variable to see corresponding changes in the response variable. Observational study is different from experiment in which we can control the independent variable. They are also referred as controlled trials.

Thus, the correct answer is

Option C) An observational study measures the value of the response variable without attempting the influence the value of either the response or explanatory variables