Some sources claim that IQ is correlated with academic and/or professional success. Let's assume there is a correlation of 0.5 between IQ and University GPA, discovered from a study of a very large group of students.
If I took an IQ test and got a score of 100, does this mean I'm less likely to achieve a high GPA? I recently heard a phrase "statistics mean nothing to the individual", meaning (I think) that just because you contracted some illness with a 95% mortality rate, that there's a 5% chance that you'll survive -- that it is incorrect to make some conclusion about an individual based off of the bigger picture derived from a large sample size.
I've read about the Ecological Fallacy (https://en.wikipedia.org/wiki/Ecological_fallacy), but that seems to apply more to summarized metrics like the mean -- you can't assume any given data-point will be close to the mean, as you have no idea of the underlying distribution of the data when given only the mean.
Is there any truth to the phrase "statistics mean nothing to the individual"?