Hainan Bikai Pharmaceutical Co. LTD. Haikou 570311 China;
Hainan Huiyuantang Pharmaceutical Co. LTD. Haikou 570311 China;
School of Business Administration Shenyang Pharmaceutical University Shenyang 110016 China;
quantitative analysis; OTC drugs; prediction of the scale of market; unit root test; granger causality test; co-integration test;