so, my question is "Whether high IQ it will affect the accuracy of one's decision making because to do Buy and Sell required the right decision-making, extensive analysis and detailed graph reading".
I don't think so. One can know how those technical indicators are computed but it would still depend on how he would apply it to his trading strategy so that he can be a profitable trader. It would still depend on how he would be able to control his emotions when trading and following his strategy without being affected by what is happening in the market.
In fact, there is a tendency that those street smarts has a high possibility of being successful because they use actual experience in learning whereas those who has high IQ maybe working for those street smarts because they are more focus on theories than those what is actually happening. This would be applicable to trading as well.