In the autumn of 2003, the National Safe KidsCampaign conducted a study of helmet use amongchildren ages 5 to 14 who participate in wheeledsports. Data were collected from various sites acrossthe United States that were designated as placeswhere children often engage in wheeled sports.Activity, apparent gender, and estimated age wererecorded for each rider, along with information onhelmet use. It was found that, overall, 41% of childrenwere wearing a helmet while participating in awheeled sport.a. Was this study an experiment or an observationalstudy?b. Identify the parameter of interest.c. Identify the statistic and give its value.d. Classify the four variables as numerical or attribute.