问答题 阅读下述摘要，请简要分析该研究的基本问题、研究思路、主要研究结论以及研究意义。【北京大学2015】 Title：Perceived Supervisor Support：Contributions to Perceived Organizational Suppo~and Employee Retention Authors：Esenberger，Robea；et a1．Journal of Applied Psychology，2002． Abstract：three studies investigated the relationships among employees’perception of supervisor support(PSS)，perceived organizational suppo~(POS)，and employee turn over．Study 1 found，with 314 employees drawn from a variety of organizations．that PSS was positively related to temporal change in POS．suggesting that PSS leads to POS．Study 2 established，with 300 retail sales employees，that the PSS—POS relationship increased with perceived supervisor status in the organization．Study 3 found，with 493 retail sales employees，evidence consistent with the view that POS completely mediated a negative relationship between PSS and employee turnover．These studies suggest that supervisors to the extent that they ale identified with the organization，contribute to POS and，ultimately，to job retention．