Someone who is not very intelligent and just happens to 'get by' in life by working in factories, doing the dullest possible jobs. Someone not equipped to handle complex issues so has no choice but to live simply. Not retarded, but not within the normal range of 100 so is incapable of doing some very simple tasks. In school, they pass with at least a C, if they even try, but will never become honor students. They are percieved as lazy, and abilities are underestimated. You can tell who the 'lower average' kids are by just looking for the one's who sleep or put their head down all day in class, or the uninsightful depressed kids who say they're worthless and without qualities and really truely are. The only way they could impress people is by either plaigarizing a book or copying an insightful comment made by someone with much more ability for cognitive functioning.
Jerry enjoyed the company of losers with low IQs because he couldn't find any real friends who actually counted, since their IQs were so very high and his wasn't even within the hundreds, being a 92 and all. Life sucks for those with IQs in the 80s or 90s.
John has an IQ in the 80s or 90s, I'm assuming, since he works the lowest paying position in the factory.
She doesn't have anything insightful to say so she must have an IQ in the 80s or 90s.