This seems like an easy statistics question. But, though, I wanted the complete details of it, as to the why's of the problem . The problem is:
The average adult population IQ is estimated to be about $100$ with a standard deviation of about $15$. Now, a new study was made on a sample of $70$ students(randomly selected from the adult population) and the resulting average was found to be $108$. Can we conclude that the average IQ of the population has really changed?
Well, according to me, the sample size is too less(intuitively, would like to know why in terms of confidence intervals or some similar stuff) and the new average being with the standard deviation, the evidence is insufficient to conclude anything. Any ideas. Thanks beforehand.