题面是这样的

Optimism and Longevity
In this exercise, the cancer specialist developed the following saturatecl model (every variable is linked to every other variable). Perform a path analysis using SPSS.

Using the SPSS data file, answer the following questions.

• Name the exogenous variable(s).
• Name the endogenous variable(s).
• Name the mediating variable(s).
• What is the beta coefficient for the direct effect of years lived and age? Is it sta­tistically and practically significant?
• How many indirect effects does age have on years lived? Is it statistically and practically significant?
• Why are standardized weights rather than nonstandardized weights used?
• What does this model tell the researcher?
• Write a results section for this research

我不太懂得如何在SPSS中计算path analysis 确定mediating variable。我猜测是看具体变量中在进行一系列多元回归时哪个变量的standardized coeefient 值比较大就说明它对于endogeous variable的影响比较大？如果是这样，我觉得可以看出数据中( 见附件）的optimism 是mediating variable 可以这么理解么？烦请对于在SPSS中计算path analysis 的老师，前辈解疑释惑。子云：不愤不启，不悱不发。鄙人愚钝，烦请解疑。谢谢！！