The difference between an observational study and an experiment is that: A. in an observational study, only one group is studied, and in an experiment, two groups are studied.
B. in an observational study, the researchers do not control treatment, and in an experiment, they do.
C. in an experiment, cause-and-effect is analyzed, and in an observational study, it is not.
D. in an experiment, one group is studied over a short period of time, and in an observational study, the group is studied over a longer period of time.

B

Step-by-step explanation:

An experiment is a study carried out in a controlled environment where the person undertaking the research hopes to understand cause and effect between the independent and dependent variables. An example of a experiment is the palovian experiment

The independent variable is the variable that the person carrying out an experiment changes or manipulates. the independent variable usually have a direct effect on the dependent variable

The dependent variable is the variable that is being measured in an experiment. It is usually affected by the independent variable

Observational study is the study where the researcher observes and measures cause and effect between independent and dependent variables without trying  to control or influence the population

answer: 230 miles ( vote ! )

step-by-step explanation:

180.39 minus 17.99 equals 162.4

then divide 162.4 by .80 to get 230