Bump.
FSIQ is not an average of the other numbers, but a measure of how rare that combination of scores is in the population. Sift through some of the other scores that people post here, and you'll see that often the memory and speed score are lower than the others, and these cause bottlenecks for the child. Your child doesn't have any such blocks.
Correct. I don't have my tables with me, so I can't speak to the exact numbers, but the general idea is that any given high Index score is pretty rare, but it's much more rare to have multiple rare events occurring in the same person, than to have a single rare event occurring in any one person. (Comparatively, splinter skills are not all that unusual in the general population, but global high skills are.)
