You're using one variable (IQ for a whole nation - which has its integrity issues alone) to paint a broad brush over a small group (Sudanese migrants). You're appealing to statistics incorrectly. It's a fallacy. Your discussion re: Indian migrants actually takes into account the demographics of those migrants but you're ignoring it for the Sudanese. This is why you're wrong.
So what exactly are you trying to say then? That while the more intelligent indians immigrate to australia (and are thus over-represented in higher educational attainment), the less intelligent of the sudanese population immigrate to australia (and are thus over-represented in crime stats)?