One would not expect it to be at the average, because this information is going to have come from some popular app, and there will be high correlation between "people who have never used even a single app: they just wanted a phone" and "people who have never considered jailbreaking: they just wanted a phone"; this is even more the case once you consider that it might not be an app that "virtually everyone has": it might be an app that is either correlated with skill (you are slightly more likely to have the app, even controlling for people who have apps at all, if you are the kind of person who really cares) or negatively correlated with age (you are more likely to have the app if you are younger, which correlates better with the demographic of people who jailbreak).