看了一个孩子的Mensa test结果通知,里面有这么一段话“ Your test paper has now been scored. Of the five intelligence indexes calculated, we use three indexes to assess eligibility for Mensa membership. Your highest of the three index scores was FII = 145; 99.9%ile . ”请问“ FII = 145; 99.9%ile”是什么意思,FII是指什么?