Regression analysis is complex and you will almost certainly need to visit the documentation at https://services.scideas.net/regression.
Example curl request would be:
curl -X POST -H “Content-Type: application/json” -d “{“outcome_variable”:“charges”,“ignore_variables”:[“sex”],“data”:[“age,sex,bmi,children,smoker,region,charges”,“19,female,27.9,0,yes,southwest,16884.924”,“18,male,33.77,1,no,southeast,1725.5523”,“28,male,33,3,no,southeast,4449.462”,“33,male,22.705,0,no,northwest,21984.47061”,“32,male,28.88,0,no,northwest,3866.8552”,“28,male,33,3,no,southeast,4449.462”,“33,male,22.705,0,no,northwest,21984.47061”,“32,male,28.88,0,no,northwest,3866.8552”,“32,male,28.88,0,no,northwest,3866.8552”]}” -H "x-rapidapi-key: " -H “x-rapidapi-host: regression.p.rapidapi.com” https://regression.p.rapidapi.com/regression/api