A town investigated whether to install a traffic light at a certain four-way intersection. Sensors were installed under the pavement at each entry to the intersection. The sensors were able to record the number of vehicles entering and exiting the intersection, which of the four roads were used, and the times of entry and exit of all vehicles using the intersection. Which of the following best describes the method used for collecting these data?ResponsesA focus groupAnswer A: A focus groupAA controlled experimentAnswer B: A controlled experimentBAn observational studyAnswer C: An observational studyCA survey with a questionnaire

To determine the best method used for collecting the data in the given scenario, let's analyze each option:

A focus group: This involves gathering a small group of people to discuss and provide feedback on a specific topic. It is not applicable here as the data collection involves sensors and not direct human interaction.

A controlled experiment: This involves manipulating one or more variables to observe the effect on another variable, typically with a control group for comparison. In this case, there is no mention of manipulating variables or having a control group.

An observational study: This involves observing and recording data without manipulating any variables. The sensors recorded the number of vehicles, the roads used, and the times of entry and exit without any intervention.

A survey with a questionnaire: This involves asking people questions to gather data. There is no mention of asking drivers or pedestrians any questions in this scenario.

Given the description, the best method used for collecting these data is:

Answer C: An observational study